Photocatalytic and Superhydrophilic Surfaces Workshop

PSS2013

Manchester Museum

12th/13th December 2013

Final Programme and Book of Abstracts 

PSS2013

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Organising Committee: Prof Peter Kelly, MMU – Conference Chair Prof Joanna Verran, MMU Dr Glen West, MMU Prof Andrew Mills, Queen’s University Belfast Prof Norman Allen, MMU (retired) The Organising Committee would like to thank the UK and Ireland Semiconductor Photochemistry Network and the Institute of Physics, Ion and Plasma Surface interaction Group for their support of this workshop.

http://ukispc.org.uk/

http://www.iop.org/activity/groups/subject/ipsi/

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Photocatalytic and Superhydrophilic Surfaces Workshop, PSS 2013

Final Programme

12th – 13th December 2013, Manchester Museum

Day one

09:30 Registration and coffee

09:55 Opening remarks from the Chair Session One – Applications in Health and Hygiene.

Chaired by Prof Val Edwards-Jones

10:00 Invited Presentation 1: Peter Hoffman, Public Health England

Preventing healthcare infections with antimicrobial surfaces – the challenges

10:30 Invited Presentation 2: Prof Tony Byrne, University of Ulster

Photocatalytic coatings for healthcare applications

11:00 Break and Posters Session Two – Fundamentals and Modelling.

Chaired by Prof Norman Allen

11:20 Invited Presentation 3: Dr Terry Egerton, University of Newcastle

UV absorption - the fundamental step in photocatalysis, and some practical consequences

11:50 Paper C1 – Dr Javier Marugán, Universidad Rey Juan Carlos, Madrid

CFD modelling of photocatalytic systems

12:10 Paper C2 – Dr Petr Dzik, Brno University of Technology, Czech Republic

UV-LED based reactors for automated photocatalytic activity assessment

12:30 Lunch and Poster Session

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Session Three – Production and Testing.

Chaired by Prof Peter Kelly

13:30 Invited Presentation 4: Prof Andrew Mills, Queen’s University Belfast

The wonders and worries of dye bleaching by semiconductor photocatalysis

14:00 Paper C3 – Svava Davíðsdóttir, Technical University of Denmark:

Investigations on photocatalytic TiO2 coatings produced by magnetron sputtering process

14:20 Paper C4 – Anže Abram, Jožef Stefan Institute, Ljubljana, Slovenia:

Hydrothermal passivation of zinc substrates

14:40 Paper C5 – Dr Marina Ratova, Queen’s University Belfast:

HiPIMS deposition of crystalline titania photocatalytic coatings at low temperature” 15:00 Break and Posters Session Four – Environmental Applications Part 1.

Chaired by Dr Glen West

15:20 Invited Presentation 5: Prof Gianluca Li Puma, Loughborough University

Engineering Applications of Heterogeneous Photocatalysis for Environmental and Renewable Energy Production

15:50 Paper C6 – Dr Rosanna Grilli, University of Surrey

Surface Characterization and Photocatalytic Performance N-doped TiO2 thin films Deposited by Sol-gel Methods

16:10 Paper C7 – Šárka Paušová, ICT Prague, Czech Republic:

Preparation of TiO2-SiO2 Composite Materials for Environmental Use 16:30 Break 17:30 Poster Session. Drinks and canapés served from 18:00 19:00 Evening Meal in the Fossil Gallery: ‘Dining with Dinosaurs!’

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Day two

08:30 Registration and coffee Session Five – Antimicrobial Testing and Applications

Chaired by Prof Peter Kelly

09:00 Invited Presentation 6: Prof Joanna Verran, MMU

Assessing the antimicrobial properties of photocatalytic coatings: Problems and solutions

09:30 Paper C8 – Dr Leanne Fisher, MMU

Production and characterisation of photocatalytic surfaces for use in process hygiene in the brewing industry

09:50 Paper C9 – Dr John Kiwi, Ecole Polytechnique Fédérale de Lausanne

Solar light-induced antibacterial activity of RF-plasma and UVC light pretreated polyethylene-TiO2 thin films. Evidence for increased cell wall fluidity

10:10 Paper C10 – Martina Lorenzetti, Jožef Stefan Institute, Ljubljana

Photoinduced properties of hydrothermally synthesized anatase coatings for medical devices

10:30 Break and Posters Session Six – Photocatalytic Testing Methods and Standardisation.

Chaired by Prof Joanna Verran 10:50 Invited Presentation 7: Frank Neumann, Fraunhofer IST

An overview of standardized photocatalytic test methods

11:20 Invited Presentation 8: Tobias Graumann, Fraunhofer IST

Development of a rapid photocatalytic self-cleaning test

11:50 Paper C11 – Dr Michael Nolan, Tyndall National Institute, Cork

Design of Visible Light Activated TiO2 Photocatalysts from First Principles Simulations

12:10 Lunch and Poster Session 12:40 Open forum to discuss:

‘Standards for photocatalysis – bringing clarity to test methods’ Chaired by Peter Hatto, Director of Research Ionbond UK Ltd and convenor of working groups on test methods for ceramic coatings in CEN TC 184 and ISO TC 206.

All welcome

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Session Seven – Industrial Applications.

Chaired by Dr Glen West

13:20 Invited Presentation 9: Claire Bunting, Pilkington Technology Management, NSG

Scale-up challenges of a commercial photoactive product

13:50 Paper C12 – Dr Jones Alami, INI Coatings:

Super-hydrophilic titanium oxide thin coatings for dental implants by ionized sputtering

14:10 Paper C13 – Dr Parnia Navabpour, Miba Coating Group. Teer Coatings Ltd:

TiO2 and doped TiO2 coatings deposited by reactive magnetron sputtering for medical and food processing surfaces

14:30 Paper C14 – Dr Jarkko Saarinen, Abo Akademi University:

Photocatalytic wettability conversion of TiO2 nanoparticle coated paperboard 14:50 Break and Posters Session Eight – Environmental Applications Part 2.

Chaired by Prof Peter Kelly

15:10 Invited Presentation 10: Prof Pierre Pichat, CNRS/Ecole Centrale de Lyon

An overview of the environmental applications of photocatalysis

15:40 Paper C15 – Tatiana Ivanova, ASTRaL, Lappeenranta University of Technology

Enhancement of atmospheric plasma decomposition of toluene using porous dielectric conformally coated with titanium dioxide by atomic layer deposition

16:00 Paper C16 – Prof Carlos Tavares, University of Minho, Portugal

Controlled release of volatile compounds from polymeric microcapsules mediated by photocatalysis

16:20 Closing remarks and end of workshop

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Poster Presentations

No. Presenter Affiliation Title

1 Jonathan Dervaux  

U of Mons Synthesis of ultra‐porous crystalline TiO2 thin films by glancing angle reactive magnetron sputtering  

2  Raechelle A. D’Sa  U of Liverpool Covalent grafting of hyaluronic acid onto PMMA for antibacterial applications 

3  Marcela Kralova Brno University of Technology 

Study of physical properties and photocatalytic activity of zinc titanate 

4 Muhammad Subkhi Sadullah 

King Fahd Uni of Petroleum and Minerals 

Facile Method for Fabrication of TiO2 Films for Underwater Superoleophobic Applications 

5  Franziska Knies  EMPA  Superhydrophilic ceramic glazes for sanitary ware 

6  Imane Sayah  IRTES‐LERMPS/UTBM  Microstructural and photocatalytic properties of nanostructured TiO2/Au prepared by reactive magnetron sputtering 

7  Ashlene Vennard  U of Ulster  Surface disinfection using Photocatalytic coatings 

8  Michal Veselý Brno University of Technology 

Antimicrobial activity of printed hybrid titania/silica transparent layers 

9  Vit Kasparek Brno University of Technology 

Photocatalytic water splitting by anatase‐brookite biphasic nanoparticles  

10 Anita Trenczek‐Zajac 

AGH University of Science and Technology 

Superhydrophilic behaviour of TiO2 nanotubes 

11  Agnieszka Lacz AGH University of Science and Technology 

Effect of QDs sensitization on the photoelectrochemical behaviour of TiO2

flower‐like nanostructures 

12  Antony Scimone  MMU Putting theory into practice: monitoring performance of photoactive coatings on a Manchester wall 

13  Yao Lu  UCL  Preparation of superamphiphobic surfaces on titanium substrates

14  AA Abdel‐Wahab  Assiut University  TiO2 – Based Photocatalytic Oxidation of Paracetamol 

15  Jonathan Watté  U Of Ghent Low temperature deposition method for producing transparent and photocatalytically active TiO2 layers  

16 Polycarpos Falaras  

NCSR “Demokritos”   Photoinduced pollutant removal using nanostructured TiO2 thin films  

17 Polycarpos Falaras  

NCSR “Demokritos”  Visible light active titania thin film photocatalysts  

18  Justyna Zatorska West Pomeranian University of Technology 

Production of self‐cleaning cement containing modified titanium dioxide  

19  Kamila Bubacz West Pomeranian University of Technology 

Photocatalytic discoloration of organic dye on building gypsum plasters containing co‐modified TiO2‐N,C under UV or Vis irradiation 

20 Ewelina Kusiak‐Nejman 

West Pomeranian University of Technology 

Preparation of visible light‐active TiO2 by thermal modification with naphthalene  

21  Cristina Bogatu Transilvania University of Brasov 

Influence of pH and H2O2 on Tungsten Oxide and Fly Ash Mixtures for Dye Removal from Wastewater 

22  Maria Visa Transilvania University of Brasov 

New Composites Obtained by Freundlich Conditions for Advanced Wastewaters Process 

23  Michal Baudys Institute of Chemical Technology Prague 

Photocatalytic activity of paints containing commercial ZnO and TiO2

photocatalysts 

24  Nasir Ahmed King Fahd Uni of Petroleum and Minerals 

Water Disinfection strategies using Solar Photo catalysis  and some prototype devices for small scale water purification 

25 Mohammad Ashraf Gondal 

King Fahd Uni of Petroleum and Minerals 

Photo‐induced Superhydrophilicity and Underwater Oil Repellency of TiO2

Films and their Application for Oil Water Separation 

26  J Hamilton  U of Ulster Probing the Mechanism of Visible Light Photoactivity using Photoelectrochemistry 

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Abstracts

IP1: Preventing healthcare infections with antimicrobial surfaces – the challenge

Peter Hoffman

Public Health England

To demonstrate that a surface has antimicrobial properties is not necessarily an indication that it will be an effective component of an infection prevention strategy in healthcare. For such a surface to have a positive contribution, it needs to target a significant route of transmission and to be effective in realistic conditions. There is a usually substantial gap between a demonstration of potential in carefully controlled laboratory observations and the possibility of any contribution in real life. This talk will explore the nature of infection transmission in healthcare, and the questions and variables that need to be considered. Amongst those will be: Is the targeted contamination relevant? Hospitals are not sterile zones, nor do they need to be. Are there better ways of controlling relevant contamination? Particulate air filters, for example, are a monitorable established technology. For the few areas where control of airborne contamination is required, antimicrobial filters offer questionable advantages. Will it work in a realistic time-frame? Frequent hand contact surfaces would need to be self-decontaminating in a matter of seconds. Will it work in the level of organic matter likely to be present? Organic matter interferes with antimicrobial action. Tests are normally carried out using microbial suspensions in water; this is not how patients produce their contamination. Will the technology be effective against a relevant range of microbes? Bacterial spores (Clostridium difficile being the most prominent example) are usually vastly more resilient than most other microbes. To demonstrate microbial killing is relatively simple; to indicate reliable and effective infection prevention is a very different proposition.

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IP 2: Photocatalytic coatings for healthcare applications’

J Anthony Byrne

Nanotechnology and Integrated BioEngineering Centre University of Ulster, Northern Ireland, BT37 0QB

j.byrne@ulster.ac.uk

There is a need for new or complimentary methods of disinfection to combat the on-going problem of healthcare associated infections (HAI). An HAI is defined as an infection which was not present upon patient admission to the hospital (clinic or care facility), but is contracted during the hospital stay. According to figures published by Worcester Infection Control in 2009 [1] more than 300,000 people each year are affected by an HAI. At any one time 8.2% of patients have an HAI. On average a person with an HAI will spend over 2.5 times longer in hospital, cost over £3,000 more to treat and often requires treatment after discharge. The cost to a typical NHS Trust of treating HAI is £3.6m a year. It is estimated that 5000 patients die a year because of HAI and it contributes to the deaths of a further 15,000 others. The cost of HAI to the NHS is approximately £1 billion a year. Susceptible patients within the hospital can contract disease readily as they are they at risk from their own endogenous flora as well other hospital pathogens, which are capable of spreading through the air, in water or possibly from contact with contaminated surfaces. Although the extent of this risk has not been clearly established, it is known that hospital surfaces and/or medical devices can become contaminated with infectious pathogens which can potentially play a role in the spread of HAI. Increased or more stringent cleaning regimes are recommended to help reduce incidence of HAI. Heterogeneous photocatalysis is a potential complementary solution to reducing the risk of HAI. Photocatalysis has been shown to be effective for the inactivation of a wide range of microorganisms including clinically relevant organisms [2]. Photocatalytic coatings may be applied to surfaces in healthcare environments so that a residual decontamination effect is present under ambient or natural lighting. If the photocatalyst is TiO2 UV sources might be used (but this may not be practical) or there is a small component of UV in the fluorescent lighting commonly used for indoor lighting. Modification of the TiO2 e.g. non-metal doping may be used to increase the visible light activity. TiO2 coatings with UV excitation may be applied for disinfection or decontamination in medical devices. This paper will present past and present work at the University of Ulster concerned with disinfection and decontamination of surfaces for application in healthcare environments and medical devices. [1] Worcester Infection Control (2009), Facts and Figures, Available online at http://www.worcesterinfectioncontrol.nhs.uk/ [date accessed 31 July 2013)

[2] P.S.M. Dunlop, C.P. Sheeran, J.A. Byrne, M.A.S. McMahon, M.A. Boyle, K.G. McGuigan, (2010) Inactivation of clinically relevant pathogens by photocatalytic coatings, J. Photochem. Photobiol. A., 216, 303–310

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IP3: UV absorption - the fundamental step in photocatalysis, and some practical consequences

Terry A. Egerton

University of Newcastle

Most semiconductor-photochemistry studies focus on reactions of the photogenerated charge-carriers at the oxide surface – e.g. do electrons and/or holes transfer directly to species adsorbed on the surface or do they form catalytically active hydroxyl radical intermediates? Other papers consider the recombination reactions which control the proportion of charge carriers that reach the surface – e.g. how does the presence of a transition metal modify charge-carrier recombination and thus modify photonic efficiency. By contrast, this paper concentrates on the first photochemical step, photon absorption. Three different facets of UV absorption by semi-conductor particles will be considered. Discussion of the influence of particle size on UV absorption will be summarized. Just as particle size affects light scattering, so too is light absorption modified. But what is the particle size in the application? Examples from three commercially important practical systems, (a) paints, (b) pigmented polymer films, and (c) inorganic-sunblocks for cosmetics, will be used to show that a semi-conducting oxide can provide protection from direct photochemical degradation. The semi-conductor may protect wooden substrates, polymeric packaging materials and human skin from UV. Finally the effect of UV absorption on the studies of the photocatalytic degradation of aqueous solutions of organics will be considered for two separate cases. First, what are the consequences of UV absorption by the liquid in which the catalyst is dispersed? Second, what is the effect on the rate of photocatalytic reaction when the effective particle size of the catalyst is changed?

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C1: CFD modeling of photocatalytic systems

J. Marugán, C. Casado, R. Timmers, R. van Grieken

Department of Chemical and Environmental Technology, ESCET, Universidad Rey Juan Carlos, C/ Tulipán s/n, 28933, Móstoles, Madrid, Spain (javier.marugan@urjc.es)

The kinetic description of photocatalytic processes requires the evaluation of the radiation profiles inside the system. As the process is activated by absorption of photons, their availability will decrease as the radiation penetrate in the semiconductor material leading to unavoidable profiles of radiation and consequently of reaction rate values. Despite the extensive laboratory research done in photocatalytic processes, there are only few investigations of the application of computational fluid dynamics (CFD) to photocatalytic reactors. The use of CFD tools allows the rigorous description of complex physicochemical processes that involve a large amount of mathematical computations. The aim of this study was to develop a CFD-based model that integrates hydrodynamics, species mass transport, chemical reaction kinetics, and irradiance distribution within the reactor. An annular photoreactor configuration has been studied using methanol as model pollutant. Different hydrodynamic models were evaluated in terms of their mass transfer prediction capabilities. The fluid was assumed to be Newtonian, incompressible and isothermal with constant physical properties. Photocatalytic reaction is considered to occur only in the internal wall of the reactor, coated with a thin film of TiO2. The lamp was defined as a solid continuum cylinder, longer than the reactor to minimize end effects. The TiO2 layer wall was set as a 1-mm thick. The refractive index and absorption coefficient, optical properties of the materials necessary for the simulations, have been taken from the literature. The water inside the annulus was defined as a fluid continuum. The used grids had a number of volume cells enough to give mesh-independent results. In the studied system the velocity and radiation fields did not interact. So, the CFD model can be solved in three steps. First, the equations of conservation of mass and momentum were solved for getting the flow field across the computational domain. Then, the velocity values were kept and the radiation field was solved, and finally, the conservation of species equation was solved. Experimental data obtained in a wide range of values of the main variables of the process provides validation for the model.

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C2: UV-LED based reactors for automated photocatalytic activity assessment

P. Dzik, M. Veselý

Faculty of Chemistry, Brno University of Technology, Czech Republic

While a lot of research attention has been paid to the exploiting of solar radiation as excitation source for photocatalysis, artificial UV sources are preferred for laboratory scale experimental work. Mercury vapour lamps represent the oldest and most common design of artificial UV sources. They have been supplemented by a great choice of fluorescent tubes available in many different shapes and power ratings. Xenon lamps, either pulsed or continuous, represent an interesting alternative if continuous UV-Vis spectrum is required. However, all these sources are physically bulky, require mains voltage power supply and produce significant amount of heat, which makes them awkward to fit into small scale laboratory reactors. Recently, LEDs with reasonable radiation flux and wavelengths down to the UV-C spectral region have become commercially available. Their compact construction makes them especially suitable for their employment in compact photocatalytic reactor designs and/or their integration into the measuring compartments of existing conventional measuring machines (e.g. IR and UV spectrometers). We would like to report on four such experimental setups which have been designed, manufactured and conveniently used in our lab:

1. water droplet contact angle measurement chamber equipped with down-facing UV-LED intended for hydrophilization rate measurement,

2. integrated UV-LED and transmission sample holder fitting into FTIR spectrometer for monitoring of fatty acid concentration changes,

3. dedicated glass plate reactor featuring UV-LED actinic radiation source and 620 nm visible LED as measuring light source for monitoring of transmittance changes of redox dye ink layers,

4. compact cuvetted-based reactor for monitoring photocatalytic activity by fluorescence probes.

Since the actinic radiation source is fixed in the reactors, the sample exposure is continuous and so is the measurement. This results into the total elimination of sample manipulation during experiments, thus minimizing the operator-induced variables. Moreover, very dense kinetic data sets can be easily recorded by the automated data collection function available in most measuring software applications. All these set-ups proved to deliver very consistent and highly repeatable results.

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IP4: The wonders and worries of dye bleaching by semiconductor photocatalysis

Professor Andrew Mills

Queen's University Belfast

E-mail: andrew.mills@qub.ac.uk The oxidative photobleaching of dyes is one of the most dramatic and oldest ways used to demonstrate the presence of a photocatalyst material. One of the most commonly used dyes for this purpose is methylene blue (MB). Indeed, the photocatalysed bleaching of methylene blue is now an ISO standard. However, there are many very different processes, other than photocatalysis, that can be responsible for the photobleaching of a test pollutant dye. These include: photolysis, reductive bleaching and dye sensitisation. In this talk we explore these major culprits using MB as the test dye1 and possible ways in which they can be avoided. (1) A. Mills, Appld. Catal. B: Environmental, 2012, 237, 7.

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C3: Investigations on photocatalytic TiO2 coatings produced by magnetron sputtering process

Svava Davíðsdóttir, Kai Dirscherl, Rajan Ambat

Materials and Surface Engineering, Department of Mechanical Engineering, Technical

University of Denmark, DK 2800 Lyngby, Denmark

In recent years, there has been considerable interest in the use of self-cleaning surfaces on structural materials for various engineering applications. The industrial sectors such as architecture, health and food have considerable interest in exploring the benefits of self-cleaning function to increase visual appearance, air purification, and to obtain hygiene surfaces. This paper presents an overview of the investigation carried out on magnetron sputtered TiO2 coatings on aluminium alloy and steel substrates as a function of various parameters including substrate surface finish, coating thickness, and sputtering parameters. Effect of these parameters on the photocatalytic activity was investigated using methods such as high resolution electron microscopy (FEG-SEM, FIB, and TEM), AFM, SKPFM, DC polarization methods and AC impedance measurements. Photocatalytic effect was also investigated under wet condition using methylene blue decomposition, while in gas phase using a combination of Quartz Crystal Microbalance (QCM) with TiO2 coated crystals and measurement of carbon dioxide due to the decomposition of the organic compounds. In general results show that the photocatalytic activity increases with increase in thickness of the coating, while saturation is attained above a thickness level, for a given wavelength and intensity of light, due to the diffusion length and the lifetime of the electron and holes formed in the TiO2 coating. Impedance measurement shows linear increase in capacitance with thickness of TiO2. Photocatalytic activity of the coating was influenced by the nature of the interfacial oxide sandwiched between the substrate and TiO2 coating.

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C4 : Hydrothermal passivation of zinc substrates

A. Abram1 2, G. Dražić1 2 3

1Department for Nanostructured Materials K7, 'Jožef Stefan' Institute, Ljubljana, Slovenia

2Jožef Stefan International Postgraduate School, Ljubljana, Slovenia 3National Institute of Chemistry, Laboratory for materials chemistry, Ljubljana, Slovenia

Jamova cesta 39, 1000 Ljubljana, Slovenia Controlled passivation of zinc substrates has been of great interest as a way for obtaining final products with surface that won’t change with time. Zinc undergoes rapid passivation even at room conditions in the presence of water. It is therefore crucial that the surface is coated properly beforehand. Hydrothermal process offers the means to tailor the formation of zinc oxide (ZnO) layer on zinc substrate. ZnO is also a semiconductor material, displaying photocatalytic properties, so the passivized layer could be beneficial both as a protection of substrate as well as a functionalized coating. Surface of zinc substrates was cleaned in acetone and placed in ultrasonic bath for 10 minutes. Discs were then immersed in autoclave suspension and hydrothermally threated for 2--12 hours at 80--120 °C. Different solvents were used in order to limit the natural passivation. In few cases, zinc nitrate hexahydrate (Zn(NO3)2 · 6H2O) was added to the initial solution as a source of zinc ions in order synthesise ordered ZnO structure. Coatings were characterized with several techniques (XRD, AFM, SEM, TEM/SAED, EDXS) and their photocatalytic efficiency was measured with the oxidation of caffeine in the presence of UV illumination and quantified by UV/VIS spectroscopy. Caffeine was used as an indicator for photocatalytic activity because the mechanism of its degradation is well known and UV/VIS spectra of degradation products do not overlap with main caffeine peek. A petri dish with 5ml of 10ppm caffeine solution was prepared. A magnetic stirrer and coated aluminium disc were placed side by side in the solution. As prepared sample was left for 30 min in sterilizer (no UV) before it was sampled. After UV lights were turned on, solution was measured in hourly intervals and analyzed in UV/VIS spectrophotometer. Caffeine degradation of 20% was observed for passivized samples after 3 hours.

Fig. 1: SEM image of

hydrothermally threated zinc substrate

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C5: HiPIMS deposition of crystalline titania photocatalytic coatings at low temperature

M. Ratova, G.T. West, P.J. Kelly

Surface Engineering Group, School of Engineering, Manchester Metropolitan University,

John Dalton Building, Chester Street, Manchester M1 5GD, UK Titanium dioxide is a material known for its ability to initiate photoreactions under light irradiation. It is the most widely used photocatalyst due to its low toxicity, low cost and durability. Of the known crystal phases of titania, the highest photocatalytic activity is normally observed for the anatase crystal phase or for the mixed phase of anatase/rutile. Titania coatings directly deposited by conventional magnetron sputtering tend to have an amorphous microstructure. For crystalline structure to develop, post-deposition thermal treatment is typically required, with the anatase crystal phase generally forming at temperatures in excess of 400 ºC. This significantly limits the choice of materials that may be used as a substrate for photocatalytic coatings. High Power Impulse Magnetron Sputtering (HiPIMS) utilizes short pulses of power at low duty cycles (with on/off time ratio less than 10%) which results in high power densities at the target, a higher degree of ionisation of the coating flux and enables deposition of crystalline titania films with no further heat treatment required. Similarly to pulsed DC magnetron sputtered coatings, doping of titania coatings deposited by HiPIMS with metal / non-metal elements, allows enhancement of the photocatalytic properties of the coatings and improvement in their efficiency under fluorescent / visible light. In the present work, pure and doped titania coatings were deposited by HiPIMS onto a variety of substrates, including various polymeric materials. The photocatalytic properties of the coatings were assessed by their ability to degrade the organic dye methylene blue under UV and fluorescent light irradiation. The photocatalytic properties of the coatings were assessed using the degradation of methylene blue organic dye. The absorption of methylene blue with the characteristic peak at 664 nm was monitored continuously for 1 hour.

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IP5: Engineering applications of heterogenous photocatalysis for environmental and renewable energy production

Gianluca LI PUMA

Environmental Nanocatalysis & Photoreaction Engineering, Department of Chemical Engineering, Loughborough University, Loughborough LE11 3TU, United Kingdom.

Email: g.lipuma@lboro.ac.uk

Photocatalytic processes over semiconductor surfaces have attracted significant attention in recent years as potentially efficient, environmentally friendly and low cost methods for water/air purification as well as for hydrogen production by splitting of water. The process involves the irradiation of a semiconductor material like titanium dioxide (TiO2) with light energy equal to or greater than its band gap energy (Ebg). This may cause a valence-band electron to be excited to the conduction band, causing charge separation. The photogenerated electrons and holes can then migrate to the surface and participate in subsequent dark, oxidation-reduction reactions with species adsorbed on the photocatalyst surface to yield final products. Electron-hole recombination reduces the efficiency of the photo-chemical process. In this study, semiconductor photocatalyst nanostructuring methods to retard electron-hole recombination will be presented, including metal-doping, semiconductors coupling and carbon nanotubes-TiO2 nanocomposites. The engineering fundamentals of photocatalytic reactor design, photon transport and reactor modeling will be shown with examples of environmental applications for indoor air purification and water purification. The photocatalytic degradation of waste material in aqueous solutions and simultaneous production of hydrogen was also studied with the double purpose of environmental remediation and renewable energy production. Both powdered and immobilized Pt/CdS/TiO2 photocatalysts were used to oxidize model inorganic (S2-/SO3

2-) and organic (ethanol) sacrificial agents/pollutants in water. The results show that it is possible to produce hydrogen efficiently (20% quantum efficiency at 470 nm) by using simulated solar light and by photocatalytically consuming either inorganic or organic substances. CdS-rich photocatalysts were found to be more efficient for the photodegradation of inorganics, while TiO2-rich materials were more effective for the photodegradation of organic substances. The process of hydrogen by photo-reforming of glycerol from biomass waste (biodiesel wastewater) over platinized titania (Pt/TiO2) was scaled-up from laboratory scale to pilot-scale comprising a compound parabolic collector (CPC) and a tubular reactor. The results show that for the same footprint under solar irradiation, the tubular reactor could be more efficient than the CPC. The rates of hydrogen production in the laboratory scale reactor were of a few micromoles/min. Typical rates of hydrogen production in the pilot scale reactors were of the order of several hundreds micromoles/min. References: Li, Z., Gao, B., Chen, G.Z., Mokaya, R., Sotiropoulos, S., Li Puma, G. Carbon nanotube/titanium dioxide (CNT/TiO2) core-shell nanocomposites with tailored shell thickness, CNT content and photocatalytic/ photoelectrocatalytic properties, (2011) Applied Catalysis B: Environmental, 110, pp. 50-57.

Daskalaki, V.M., Antoniadou, M., Li Puma, G., Kondarides, D.I., Lianos, P. Solar light-responsive Pt/CdS/TiO2 photocatalysts for hydrogen production and simultaneous degradation of inorganic or organic sacrificial agents in wastewater, Environmental Science and Technology, 44 (2010) 7200-7205. Acknowledgement This work was supported by a project funded by E.ON AG as part of the E.ON International Research Initiative in collaboration with D. Kondarides, P. Lianos and X. Verykios from Patras University, Greece.

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C6: Surface characterization and photocatalytic performance N-doped TiO2 thin films deposited by sol-gel methods

R.Grilli1*, M.A.Baker1, D.Di Camillo2, L.Lozzi2, I.Horovitz3, H.Mamane3, D.Avisar3

1The Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences,

University of Surrey, Guildford, Surrey, GU2 7XH, UK 2Dipartimento di Scienze Chimiche e Fisiche, Università degli Studi dell’Aquila, Via Vetoio,

67010 Coppito, L’Aquila, Italy 3School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv

69978, Israel *Corresponding author (r.grilli@surrey.ac.uk)

TiO2 has been object of extensive investigation because of its many applications, including the degradation of organic pollutants. TiO2 acts as a photocatalyst under UV irradiation. Such activity could be extended to visible-light through doping, and one of the most promising dopants is nitrogen [1, 2]. In this work, a sol-gel method was developed to deposit photocatalytically active thin films of N-doped TiO2. The solution was applied onto 200 µm pore diameter Al2O3 membranes through the use of manual pipette droplets or a spiral bar applicator followed by annealing at 450°C to form a crystalline coating. The films were characterised by XPS, SEM, XRD and EDX. The photocatalytic activity (PCA) was quantified through measuring the degradation of carbamazepine (CBZ), in a flow cell using a solar simulator as a light source. Both films showed the presence of a single anatase phase, and a total nitrogen concentration of 0.9 at.%. The XPS N 1s spectra show different N states which are attributed to interstitial and substitutional nitrogen atoms and adsorbed N species. The surface morphology of the coatings deposited by the two methods was very different. The thin film deposited by pipette exhibited a more uniform but thinner layer than the inhomogeneous thicker and ‘mud cracked’ morphology of the coating deposited by spiral bar. For both methods, the PCA performance, tested on similar specimens from the same batch, was very good, with CBZ removal being above 60% after 2 hours. The coated membranes are useful for water filtration and purification, where the coated Al2O3 membrane provides mechanical filtration and bacteria removal, while the surface N-doped TiO2 coating exposed to sunlight can break down pollutant molecules and deactivate viruses. Such filters have been optimised in the frame of the European project NATIOMEM, and a pilot plant has been built for water filtration in Jordan. Initial results from the pilot plant will be presented. [1] R. Asahi, T. Morikawa, Chemical Physics 2007, 339, 57

[2] M.A. Henderson Surface Science Reports, 2011, 66, 185

18  

C7: Preparation of TiO2-SiO2 composite materials for environmental use

Š. Paušová1 2, J. Krýsa1, V. Prevot2, G. Mailhot2

1 ICT Prague, Technická 5, 166 28 Prague, Czech Republic (sarka.pausova@vscht.cz)

2 ICCF - UMR 6296, Université Blaise Pascal, 63000 Clermont-Ferrand, France Nanocrystalline anatase titanium dioxide became the most promising photocatalytic material used for complete degradation of pollutants in aqueous and gaseous phase. These days, anatase titanium dioxide is used as a photocatalyst for the preparation of photoactive coatings or paints. The main problem with use of anatase is that the photocatalytic degradation is non-selective process and binders or polymeric substrates are also degraded along with pollutants. The goal of this study is to find a way how to eliminate this problem. From preliminary studies it results that multicomponent nanocomposite materials based on the combination of titanium dioxide and silica can be the suitable solution [1]. SiO2 is not photocatalytic active material and in the composite material it can act as a barrier which separates an active surface of TiO2 from the contact with binder or polymeric substrate. TiO2/SiO2 composite materials were prepared from aqueous suspensions of each compound. Colloidal suspension of TiO2 was prepared by hydrolysis of TiCl4 at room temperature. As a source of SiO2 the commercial product (Ludox AS30, pH 9.4, stabilized with ammonia) was used. The TiO2/SiO2 composites were successfully prepared as a powder, obtained from the precipitation of mixed TiO2 and SiO2 colloidal suspensions. It was found that precipitation of prepared amorphous TiO2 in the presence of SiO2 leads to the crystallization of TiO2 powder in anatase modification. From obtained powders, the layers were prepared by sedimentation method. Photocatalytic activity of the layers was tested by the degradation of a model compound, hexane. The flow of carrier air was 1 Ndm3.min-1 and hexane inlet concentration was 4 ppm. The maximum conversion reached was around 30% which corresponds to hexane degradation rate 0.1 mmol.m-2.h-1. In future work, these materials will be tested in photocatalytic coatings and paints, to verify the positive influence of SiO2 in composite. [1] S. Ikeda, H. Kobayashi, Y. Ikoma, T. Harada, T. Torimoto, B. Ohtani and M. Matsumura, Physical Chemistry Chemical Physics, 9 (2007) 6319. Acknowledgements Authors acknowledge the financial support from specific university research (MSMT No 20/2013). Šárka Paušová thanks also to the French Embassy in Prague

19  

IP6: Assessing the antimicrobial properties of photocatalytic coatings: problems and solutions

Joanna Verran

Manchester Metropolitan University, Manchester, UK

The development of robust and effective photocatalytic coatings requires considerable expertise across a range of disciplines. Characterisation and evaluation of effectiveness demands additional skills. This is particularly true with regard to the assessment of antimicrobial properties. Assessing the antimicrobial properties of photocatalytic coatings requires considerable dexterity and patience – it is of course possible to train non-microbiologists to perform such tests, but motivation and experience is not always what it should be! Repeat sampling and experiments are necessary so that sufficient data are available for statistical analysis. Standard methods, involving the irradiation of inoculated surfaces for specific times, with subsequent quantification of survivors, are laborious (JISZ2801/ISO27477) but should enable comparison of data between surfaces and laboratories. The organism of choice for these tests is Escherichia coli. E.coli is a well characterised bacterium, easy to grow and relatively safe to handle. However, it is a gut bacterium, an indicator of faecal contamination and as such is only appropriate in preliminary tests: microorganisms more suited to the intended point of use of the surface should be selected for subsequent testing, and additional expertise may be required in their handling. Fungi (yeasts and moulds) and algae are larger than bacteria, and the coverage of a surface by growth may be measured to assess antimicrobial properties of the surfaces. Viruses are obligate intracellular parasites – they are only able to replicate inside a living host cell. Therefore, detection relies on either the presence of specific components of the virus particle, or the use of an appropriate host cells culture for viral propagation. There is a need for more simple methods for preliminary screens for antimicrobial effectiveness. This presentation will provide an overview of existing established and novel methods, and will speculate on potential novel approaches. In any case, an interdisciplinary approach is essential to identify and develop appropriate surfaces and testing methodologies to ensure that performance in the intended application is maximised.

20  

C8: Production and characterisation of photocatalytic surfaces for use in process hygiene in the brewing industry

L. Fisher1, S. Ostovapour1 2, P. Kelly2, K. Cooke3, E. Storgårds4, J. Verran1

1 School of Healthcare Science, Manchester Metropolitan University, Manchester, M1 5GD

UK 2 Surface Engineering Group, Manchester Metropolitan University, Manchester, M1 5GD

UK 3 Miba Coating Group, Teer Coatings Ltd, Droitwich, Worcestershire, WR9 9AS UK

4 VTT Technical Research Centre of Finland, Espoo, FI-02044 VTT, Finland Process hygiene plays a major role in ensuring the quality of beer. The use of photocatalytic surfaces such as titanium dioxide (TiO2) is one approach that may be used to reduce microbial fouling. Doping TiO2 coatings with transition metals can increase photocatalytic activity under fluorescent light, making indoor applications possible. The aim of this study was to produce TiO2 doped coatings on stainless steel and to characterise and explore their potential for use in the brewing industry. Coatings of TiO2 doped with molybdenum (Mo), tungsten (W) and Niobium (Nb) were produced using magnetron sputtering. Characterisation included photocatalytic activity via the degradation of methylene blue, EDX to determine dopant percentages, XRD and Raman spectroscopy to acquire information about the crystal structure and mechanical durability tests. Antimicrobial activity was tested using three brewery isolates with and without the application of a conditioning film (beer). The addition of Mo, W and Nb enhanced photocatalytic activity under fluorescent light. The Ti-Mo coating had an anatase/rutile mixed structure whilst Ti-W and Ti-Nb were anatase. All coatings showed good adhesive properties and Ti-Mo proved the most active against the brewery organisms. The presence of dried beer on the Ti-Mo surface resulted in microbial growth over time being apparent however, a more dilute soil did not interfere with antimicrobial activity. The Ti-Mo surface was also active in the dark suggesting it could have a dual function, being antimicrobial and photocatalytic. The study revealed all three coatings had good structural, physical and mechanical properties and the Ti-Mo surface had the best antimicrobial ability. It is suggested that the Ti-Mo coating could act as a secondary barrier in helping prevent microbial proliferation between cleaning/disinfection cycles within a brewery setting. The importance of regular cleaning to prevent the build-up of heavy soiling in addition to the exploitation of functional surfaces that may reduce fouling should however be highlighted. Investigations to enhance the hygienic status of surfaces in the brewing industry using the Ti-Mo coating in comparison with stainless steel are near completion.

21  

C9: Solar light-induced antibacterial activity of RF-plasma and UVC light pretreated polyethylene-TiO2 thin films. Evidence for

increased cell wall fluidity

S. Rtimi1*, R. Sanjines2, C. Pulgarin1, A. Kulik3, J. Kiwi4

1 Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-GPAO, Station 6, CH-1015,

Lausanne, Switzerland 2 Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-IPMC-LNNME, Bat PH, Station 3,

CH-1015, Lausanne, Switzerland. 3 Ecole Polytechnique Fédérale de Lausanne, EPFL-SB –PSB-LPMV, Rte de la Sorge, CH-

1015 Lausanne, Switzerland 4 Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LPI, Bat Chimie, Station 6,

CH1015, Lausanne, Switzerland This study presents the first account on RF and UVC pretreated polyethylene (PE) subsequently DC-sputtered undergoing reversible photo-switchable hydrophobic to hydrophilic transitions under low intensity solar irradiation light. Sputtering was carried out with a Ti-target in an O2-reactive atmosphere. RF-plasma pretreated PE samples for 15 min subsequently sputtered by TiO2 for 8 min led to bacterial inactivation and sample super-hydrophilicity within 60 min. under solar simulated radiation. The ensuing sample super-hydrophilic to hydrophobic conversion in the dark required 24 h and proceeded with a rate of 8.71x10-3 min-1. PE pretreatment led to an increased TiO2 loading on the PE surface as shown by X-ray fluorescence (XRF) and X-ray-diffraction (XRD) compared to non-pretreated PE. A concomitant increase in sample rugosity was detected by atomic force microscopy (AFM). An increase of the TiOH peak at 631.9 eV for RF pretreated PE was observed compared to non-pretreated PE samples by X-ray photoelectron spectroscopy (XPS). By Fourier transform infrared spectroscopy (ATR-FTIR), a systematic shift of the a(CH2) stretching vibrations was observed for the E. coli phospholipid-layer (LPS) under light irradiation on the PE-TiO2 samples within 60 min. This discontinuous IR-peak shift reflecting an increase in LPS cell-wall fluidity was observed within the same period as the increase in sample hydrophilicity and E. coli inactivation, giving concomitant rise to the formation of malondialdehyde (MDA). The shift in the IR spectra reflect an increase in disorder in the LPS chain packing with the concomitant increase in mobility in the LPS units leading to longer intermolecular distances, with an increased fluidity within 60 min. This study shows that the discontinuous but stepwise increase in the LPS packing leads to the scission of the -CH2 bonds and ultimately to E. coli lysis.

22  

C10: Photoinduced properties of hydrothermally synthesized anatase coatings for medical devices

Martina Lorenzetti1 2, Saša Novak1 2, Spomenka Kobe1 2

1 Department for Nanostructured Materials, Jožef Stefan Institute, Ljubljana, Slovenia 2 Jožef Stefan International Postgraduate School, Jamova cesta 39, 1000 Ljubljana,

Slovenia Titanium is considered one of the most suitable materials for hard tissue replacement, due to its mechanical properties and bioinertness. It owes its biocompatibility, bioactivity and surface properties mainly to the thin naturally formed amorphous TiO2 film. In our study, nano-crystalline TiO2 anatase coating was synthesized by hydrothermal treatment (HT) of Ti-based substrates; the effects of anatase presence on the surface properties were examined. Photocatalytic activity and wetting behaviour were examined before and after UV irradiation, as the objective of the study was to verify the potential antibacterial (self-sterilizing) effect of the anatase layer. The results of organic compounds degradation by spectrophotometry and the radical production analyses by EPR technique showed that the photoactivation of the Ti-based alloys was due to the presence of the thin (<1 µm) anatase layer. Moreover, the photoinduced hydrophilic and super-hydrophilic conditions, reached after irradiation, proved the self-cleaning action of the nanostructured anatase coatings. Interestingly, recovery of the initially high wetting angle occurred within several days in dark condition. Finally, preliminary tests on plasma proteins adsorption and cells viability were conducted, in order to predict the capability of the photo-activated anatase layer to tailor in vivo bio-response. Accordingly, the results suggested that the hydrothermally synthesized anatase coatings with adequate morphology can have a large potential to be used in self-disinfection and self-sterilization of medical devices, as a result of surface photo-activation before surgery; further, the simultaneous absence of harmful effects on cells indicated that a better osseointegration of the implant may be expected.

23  

IP7: An overview of standardized photocatalytic test methods

Dipl.-Ing. (FH) Frank Neumann

Fraunhofer Institute for Surface Engineering and Thin Films, IST Bienroder Weg 54 E, 38108 Braunschweig, Germany

The development of standardized and harmonized test methods is essential to increase the competitiveness of photocatalytically active products and will finally to help to remove poor quality products from the market. Besides, standardization in the field of photocatalysis can stimulate R&D in order to assure a comprehensive consumer protection and to prevail a healthy environment. Thus, the international and European standardization bodies recently have proposed a number of new standards in order to quantify photocatalytic activity correctly. Due to the multiplicity of photocatalytic applications, the author will give an overview of the most important published CEN and ISO standards and forthcoming drafts and specifications for water and air purification, self-cleaning and microbial properties as well as for light sources and irradiation conditions for testing these properties. As a result, students, researchers and product developers will be enabled to use appropriate test methods and setups in their daily work complying with the latest standards.

24  

IP8: Development of a rapid photocatalytic self-cleaning test

Dipl.-Chem. Tobias Graumann

Fraunhofer Institute for Surface Engineering and Thin Films, IST Bienroder Weg 54 E, 38108 Braunschweig, Germany

The growing interest in photocatalytic test methods, which allow a fast qualitative and especially reliable quantitative characterization of commercial products, has created a variety of measurement techniques that are able to assess photocatalytic activity. Due to the multiplicity of applications for photocatalytically products, there are a number of existing test methods based on photooxidation, e.g. mineralization or decolourization of solids, liquids or gaseous organic and inorganic compounds. With a main focus on methods suitable to analyze self-cleaning properties based on semiconductor photochemistry the author provides an overview of methods that are suitable for the rapid quantitative characterization of photocatalysts. Furthermore, a setup based on an ISO-compliant reactor is shown, where the rapid mineralization of stearic acid applied on the photocatalyst is monitored by inline-CO2 measurements, allowing a fast and quantitative assessment of photocatalytic self-cleaning properties with minimal changes regarding existing ISO-setups.

25  

C11: Design of visible light activated TiO2 photocatalysts from first principles simulations

Anna Iwaszuk1, Hiroaki Tada2, Michael Nolan1

1 Tyndall National Institute, UCC, Lee Maltings, Dyke Parade, Cork, Ireland

2 Department of Applied Chemistry, Kinki University, Osaka, Japan michael.nolan@tyndall.ie

TiO2 Photocatalysts are intensely studied for environmental and energy applications, with two key challenges: (1) to shift the TiO2 band gap to the visible region, allowing solar energy to be used and (2) enhancing charge separation after photoexcitation. We present in this contribution a new mechanism for engineering TiO2 in a rational fashion, driven by first principles simulations: surface modification of TiO2 with metal oxide nanoclusters. We describe results from simulations and experimental work on TiO2 rutile and anatase surfaces modified with nanoclusters of transition and p-block metal oxides, including FeOx, TiO2, SnO2/SnO, and Ga2O3.

Modifying TiO2 with transition metal oxide nanoclusters induces visible light activity, which is achieved by introducing nanocluster derived electronic states above the original TiO2 valence band edge, shifting the top of the VB to higher energy and reducing the band gap. Analysis of the absorption spectrum, the optical band gap and a model of the photoexcited state of these new structures confirms the band gap reduction which is controlled by the coverage of transition metal oxide nanoclusters on TiO2. p-block metal oxides, Ga2O3 and SnO/SnO2, modified TiO2 can show band gap reduction. For tin oxide experiment and simulation show that the change in the band gap is controlled by two factors: oxidation state of tin and the TiO2 crystal polymorph, with rutile and anatase showing different properties when modified with SnO2. The stereochemical lone pair in SnO and PbO induces a band gap reduction and some simple rules for modifying TiO2 to induce visible light absorption are presented. Models of the photoexcited state of modified TiO2 allow us to examine electron and hole separation upon photoexcitation, which is important to understand non-radiative charge carrier recombination. Generally photoexcitation results in a hole on a low coordinated oxygen atom in the nanocluster and an electron in the TiO2 surface; the presence of low coordinated atoms is crucial for localisation. The metal oxidation state in tin and lead oxide modified anatase tunes charge separation. Finally, the effect of hydroxyl groups on the properties of these new structures is examined.

26  

Open forum to discuss:

‘Standards for photocatalysis – bringing clarity to test methods’

Chaired by Dr Peter Hatto1

1Director of Research Ionbond UK Ltd and convenor of working groups on test methods for ceramic coatings in CEN TC 184 and ISO TC 206.

Standards provide agreed ways of doing and making things and are of inestimable value: to industry, e.g. by providing a technical basis for contracts; to commerce, e.g. by facilitating electronic fund transfers; and to society in general, e.g. by ensuring the safety, quality and reliability of goods and services. ISO TC 206 ‘Fine ceramics’ began its work on photocatalysis standards in 2003 and has so far produced 11 international standards, with a further three in preparation and another ten in planning. These standards and proposed standards address test methods for evaluating air purification and antimicrobial properties of (semiconducting) photocatalysts under both UV and visible light. CEN TC 386 ‘Photocatalysis’ commenced its work in 2008 and has two standards currently under development, one of which, on ‘irradiation conditions for testing photocatalytic properties of semiconducting materials and the measurement of these conditions’, will be published shortly. The development of standards within ISO and CEN is undertaken by experts working on a voluntary basis for the benefit of all stakeholders. The process and quality of documents is critically dependent on the knowledge and active participation of these experts, as well as on the informed and critical review of documents by members of the wider stakeholder community. Although compliance with standards is voluntary, their utility is such that compliance frequently becomes obligatory in order to satisfy customer or regulatory requirements. Whilst standards should be ‘aimed at the promotion of optimum community benefits’, low levels of participation and review can result in poor quality standards or those favouring a particular company or country interest. It is therefore important that interested stakeholders recognise the need for and benefits of participating in standards development to ensure the publication of fair, credible, technically accurate, and usable documents. The purpose of the forum is to provide participants with the opportunity of commenting on/learning more about the suite of existing and proposed standards, and of how they can contribute to and benefit from standards development.

27  

IP9: Scale-up challenges of a commercial photoactive product

Claire Bunting

Pilkington Technology Management, Online Coatings, NSG European Technical Centre, Hall Lane, Lathom, L40 5UF

Pilkington Activ™ self-cleaning glass has currently been on the market for around 10 years. The objective of this presentation is to discuss the challenges faced in large scale production of a reproducible product which can endure subsequent processing. This will include the manufacture of coated glass, the process of forming this into a product for the end user, and some key lessons about the long term installation and use of the product.

28  

C12: Super-hydrophilic titanium oxide thin coatings for dental implants by ionized sputtering

J. Alami1, V. Stranak2

1 INI coatings LTD, Maarweg 32, 53619 Rheinbreitbach, Germany

2 Institute of Physics and Biophysics, University of South Bohemia, 370 05 Ceske Budejovice, Czech Republic

Medical devices and implants are often used in the most challenging parts of the body. For example, dental implants with hydrophilic and photocatalytic surfaces have been shown to half the time needed for the patient’s recovery post-treatment. In order to prepare such surfaces, thin layers of titanium oxide coatings with an anatase phase are deposited on the implants. The deposition process can typically last a few hours under continuous heating of the substrate. In the present paper enhanced ionization deposition (EID) of thin (200-300 nm) hydrophilic and photocatalytic TiO2 layers is performed without additional heating. It is seen that very high deposition rates are achievable when the magnetic field in front of the magnetron is designed for the specific process parameters. EID is shown thus to result in super-hydrophilic coatings with a contact angle of less than 5 degrees at a deposition rate at least six times higher than conventional deposition processes.

29  

C13: TiO2 and doped TiO2 coatings deposited by reactive magnetron sputtering for medical and food processing

surfaces

P. Navabpour1, S. Ostovarpour2, K. Cooke1, J. Hampshire1, P. Kelly2 and J. Verran2

1 Teer Coatings Ltd, Miba Coating Group, UK

2 Manchester Metropolitan University, UK Photocatalytic TiO2 and antimicrobial surfaces have been widely investigated for a number of applications where hygiene is of vital importance. Some of these applications include the surfaces used in food and beverage processing, medical devices and air purification. In this presentation, we report on photocatalytic coatings deposited using reactive Closed Field UnBalanced Magnetron Sputter Ion Plating (CFUBMSIP) from elemental targets, a more economical process than sputtering from oxide targets. Crystalline TiO2 and doped TiO2 coatings were deposited with excellent mechanical and photocatalytic properties without the need for further annealing. N, Cu and Fe were used as dopants to reduce the band gap of TiO2 in order to shift the activation of the surface to visible light irradiation. Ag had a dual function of both reducing the band gap of TiO2 and imparting antimicrobial properties to the surface; hence the Ag-TiO2 coatings were antimicrobial in the dark as well as the light. CFUBMSIP technology is capable of producing durable photocatalytic and antimicrobial coatings and is readily scalable, thus providing a competitive advantage in the production of self-cleaning surfaces.

30  

C14: Photocatalytic wettability conversion of TiO2 nanoparticle coated paperboard

J. J. Saarinen1, M. Stepien1, H. Teisala2, M. Tuominen2, J. Haapanen3, J. Kuusipalo2,

J. M. Mäkelä3, and M. Toivakka1

1Laboratory of Paper Coating and Converting, Center for Functional Materials, Abo Akademi University, Porthansgatan 3, FI-20500 Åbo/Turku, Finland

2Paper Converting and Packaging Technology, Department of Energy and Process Engineering, Tampere University of Technology, P.O. Box 589, FI-33101 Tampere, Finland

3Aerosol Physics Laboratory, Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland

Wettability of paper and paperboard is important, for example, in printing and

coating. We have recently studied wettability of paperboard coated with SiO2 and TiO2 nanoparticles deposited by a liquid flame spray (LFS) process. LFS is a versatile tool for generation of various metal and metal oxide nanoparticles with a high velocity and high temperature flame.

The metal salt precursor evaporates in the flame and nucleates forming nanoparticles that can be collected on moving substrates such as paper, paperboard and plastic film in a roll-to roll process flow.

Figure 1 shows a controlled wettability of TiO2 nanoparticle coated paperboard: the initially superhydrophobic surface can be converted to a superhydrophilic surface by an exposure to the UVA light for 30 minutes, and the initial superhydrophobicity can be recovered by a 3 min heat treatment in a high temperature oven. Moreover, these cycles can be repeated as shown in Fig. 1. The changes in the nanoscale surface chemistry during these cycles have been studied using both XPS [1] and ToF-SIMS [2] measurements. We observe a clear correlation between the UVA and oven treatment in XPS: the C/O ratio is decreased after the UVA irradiation and increased after the oven treatment. A ToF-SIMS positive ion spectra analysis shows that the amount of hydrocarbons is decreased (increased) after the UVA irradiation (oven treatment), respectively. This suggests that the TiO2 nanoparticles have a carbonaceous layer on top, which undergoes changes in response to the different treatments.

As a conclusion, we have studied the photocatalytic wettability conversion of TiO2 nanoparticle coated paperboard. UVA irradiation induces photocatalytic oxidation followed by a superhydrophilic surface that can be recovered by a heat treatment. We believe that surfaces with controllable wettability will find many applications in the near future e.g. with printed functional devices.

Finnish Funding Agency for Technology and Innovation Tekes (Grant No. 40095/11) is acknowledged for funding. JJS wishes to thank the Academy of Finland (250 122) for financial support. References [1] M. Stepien et al., Surf. Coat. Technol. 208, 73 (2012). [2] M. Stepien et al., Langmuir 29, 3780 (2013).

Figure 1. Conversion between superhydrophobic and superhydrophilic TiO2 coated paperboard surface.

31  

IP10 : An overview of the environmental applications of photocatalysis

Pierre Pichat

CNRS/Ecole Centrale de Lyon, France ; pichat@ec-lyon.fr

Commercialised or potential applications of heterogeneous photocatalysis regarding our environment cover essentially the purification of water and indoor air, and self-cleaning materials, which are mainly used in the construction industry. These applications are based on the photocatalytic oxidation of compounds. Additionally, photo-induced hydrophilicity intervenes in the case of some self-cleaning materials. The main flaw of photocatalytic degradation reactions is the slow kinetics. Consequently, it is understandable that self-cleaning materials, particularly glass, are the only application to be significantly commercialised, even if the removal of thick stains and biological solid matter poses problems in some cases. This slow kinetics is mainly due to the fast recombination rate of photogenerated charges. Until now, the numerous attempts to decrease this rate have not been sufficiently fruitful to really extend the application range, given the constraints, especially about the cost and the innocuousness. Similarly, efforts to increase the use of the solar spectrum visible region – which would be particularly interesting for self-cleaning materials – have also not been decisive so far on the commercial level. Moreover, the approach of trace organic pollutants to the photocatalyst can be hindered by adsorbed water well-organised layers, which also limits the efficacy for water and, to a lower extent, air purification. Adding a hydrophobic and organophilic adsorbent to the photocatalyst may increase the overall efficacy. Regarding indoor air purification, deposition on the photocatalyst of silica formed from Si-containing compounds present in ambient air has been discovered to be a major drawback. In addition, for some intermediate products, the photocatalytic formation rate can be higher than the photocatalytic removal rate; this can result in average concentration increases at the stationary state and hence can be a concern even for relatively low increases. Finally, the potential health risk of nano- and/or micro-particles that may be released from the photocatalytic material in water and/or air must be evaluated. Depending on the time allowed, the above topics will be detailed or simply presented.

32  

C15: Enhancement of atmospheric plasma decomposition of toluene using porous dielectric conformally coated with

titanium dioxide by atomic layer deposition

Tatiana V. Ivanova1*, Tomas Hoder2, Marja-Leena Kääriäinen1, D. C. Cameron1

1 ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli,

Finland 2 Leibniz Institute for Plasma Science and Technology , INP Greifswald e.V. Felix-

Hausdorff-Str. 2 17489 Greifswald, Germany *Corresponding author e-mail: tatiana.ivanova@lut.com

The use of atmospheric pressure plasmas together with catalysts to remove organic volatile compound (VOC) contamination from different atmospheres is a current area of research for pollution control. Dielectric barrier discharge (DBD) systems are widely used to produce non-thermal atmospheric pressure plasmas. For the most effective use of catalysts, it is necessary to maximize the surface area, which is exposed to the contaminant and to the active species from the plasma. In this research work, we have used atomic layer deposition (ALD) to deposit titanium dioxide catalytic thin film in porous glass labyrinths. ALD has been shown to produce effective photocatalytic TiO2 layers and one of its characteristics is the ability to deposit on the internal surfaces within a complex porous material. The performance of a parallel plate DBD system has been tested for the reduction of toluene. DBD systems with interelectrode material of a) uncoated porous glass and b) TiO2 coated porous glass have been studied. Porous glass has been used to increase the area of the flow path of the gases, to increase the intensity of micro discharges in the porous cavities and to maximize the surface area of the interelectrode medium. The effect of the pore size, thickness of TiO2 and specific input energy (SIE) on the conversion efficiency of the VOCs to CO2, CO and formic acid was measured. The breakdown products of the decomposition were determined by using FTIR absorption measurements for the exhaust gases. The carbon balance, which was measured, based on these products was approximately 100%. The contribution of catalytic reactions to the decomposition became increasingly dominant as specific input energy was increased. The incorporation of the ALD TiO2 enabled the complete destruction of toluene at a concentration of 2500 ppm in air with an SIE of 336 J/l.

33  

C16: Controlled release of volatile compounds from polymeric

microcapsules mediated by photocatalysis J. Marques1, P. Parpot2, C.J. Tavares1*

1 Centre of Physics, University of Minho, Guimarães, Portugal 2 Centre of Chemistry, University of Minho, Braga, Portugal.

*ctavares@fisica.uminho.pt

This work focus on the study of TiO2 nanoparticles synthesized by hydrothermal treatment and TiO2 thin film deposition by sputtering, and its application as photocatalysts for the controlled release of volatile agents (e.g., insecticides, repellents, deodorants, fragrances, etc.) from within polymeric microcapsules upon solar activation. Under ultraviolet irradiation, redox mechanisms on the semiconductor surface of the photocatalyst cleave the polymer chains of the microcapsule wall, yielding the volatilization of the encapsulated compounds [1]. The polyamide microcapsules were synthesized via interfacial polymerization from the condensation reaction of an amino group and an acyl chloride group to form a polymer film at the interface of these monomers [2,3]. The resulting microcapsules have sizes ranging from 20-150 nm. Dodecane was used as the oil core and also as the volatile agent to be released. The quantification of the output release has been performed by gas chromatography analysis coupled with mass spectroscopy. Thermal treatments were endured in order to study the influence on the optical properties, cristallinity, and surface area of the nanoparticles. These properties were correlated with the controlled release of dodecane from polymeric microcapsules and also with photocatalytic effect upon degrading a chosen dye (methylene blue).

References [1] C. Tavares, F. Pina, International Patent, WO 2011/012935 A2, 2011. [2] F. Tiarks, K. Landfester, M. Antonietti, Langmuir 2001, 17, 908-918. [3] M. Portas, J. Argilier, F. Mechin, N. Zydowicz, Polymer International, 52 (2003) 522.

Figure 1. Layers representing the heterostructured material: substrate (1); photocatalytic thin film (2); volatile agent-containing microcapsules (3).

Figure 2. Polyamide microcapsule loaded with dodecane. The release of dodecane is visible in the lower left side.

34  

POSTERS

P1: Synthesis of ultra-porous crystalline TiO2 thin films by glancing angle reactive magnetron sputtering

J. Dervaux1, P-A. Cormier1, S. Konstandinidis1, R. Snyders1 2

1Chimie des Interactions Plasma-Surface, CIRMAP, Université de Mons, Place du Parc

20, B-7000 Mons, Belgium 2 Materia Nova Research Center, Parc Initialis, Avenue N. Comernic 1, B-7000 Mons,

Belgium jonathan.dervaux@umons.ac.be

Nowadays, the efficient use of renewable energies represents a major economic and environmental issue. This is obviously also true for the solar energy, by far the most important one in term of quantity. In this context, among the many advantages of the dye sensitive solar cells, their cheap production cost is very interesting. Nevertheless, considering these cells, nowadays, the TiO2 photo-anode often consists in nanoparticles that are difficult to recycle. A potential alternative the latter would be an ultra-porous crystalline TiO2 thin film. In this work, our aim is to evaluate the potentiality of the combination of reactive Magnetron Sputtering (MS) and Glancing Angle Deposition (GLAD) in order to generate such a kind of porous coatings with a controlled crystalline constitution. The chemical composition, the crystalline constitution and the microstructure of the films are analyzed by XPS, XRD, SEM and ellipsometry, respectively. The effects of the substrate temperature and of the bias voltage on the crystalline constitution and on the porosity of the films have been evaluated.

35  

P2: Covalent grafting of hyaluronic acid onto PMMA for antibacterial applications

Raechelle A. D’Sa1, Jog Raj2, Peter J. Dickinson2, Brian J. Meenan2

1 Centre for Materials and Structures, School of Engineering, University of Liverpool, UK, L69 3GH

2 Nanotechnology and Integrated BioEngineering Centre, University of Ulster, UK, BT37 0QB

The prevention of adhesion of bacteria on surfaces of materials is of crucial importance in diverse fields such as medical devices, health care, hospital and dental surgery equipment, textiles, ship hull fouling and water purification systems.1 Once adhered on a solid surface, bacteria form colonies and subsequently biofilms that can develop into pathogenic infections.1 Generally the polymers used in the medical device industry are hydrophobic and can result in the fouling or uptake of biological components that can then mediate a host of negative biological reactions. One of the most promising ways of preventing non-specific bioadhesion is by tethering superhydrophilic macromonomers onto solid surfaces. Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan that is present ubiquitously in the extracellular matrix, vitreous humour, synovial fluid and cartilage and has the potential to provide non-fouling coatings on biological substrates if grafted in the correct conformation.3 In this study, HA was immobilised onto poly(methyl methacrylate) (PMMA) surfaces for the purposes of repelling protein, cellular and bacterial adhesion. Grafting was achieved by the following steps: treatment the surfaces with atmospheric pressure plasma processing, amination by self assembly of a 3-aminopropyltrimethoxysilane linker molecule and reaction of the surface bound amine with the carboxylic acid on HA using carbodiimide chemistry. The HA grafted PMMA surfaces showed a decrease in protein and cellular adhesion when tested with bovine serum albumin and human corneal epithelial cells, respectively. The ability of these coatings to resist bacterial adhesion was established using Staphylococcus aureus NTC8325. In this case the coatings did not repel bacterial adhesion, showing that the mechanism of adhesion of bacterial cells is different to that of mammalian cells. This indicates that conformation of the microstructure/architecture of the HA coatings is an important factor in fabricating surfaces intended to repel proteins, mammalian and bacterial cells. 1. Costerton, J. W.; Stewart, P. S.; Greenberg, E. P. Bacterial biofilms: a common cause

of persistent infections 1999, 284, 1318.

2. D'Sa, R.A.; Dickinson, P. J.; Raj, J.; Pierscionek, B.K.; and Meenan B.J. Inhibition of lens epithelial cell growth via immobilisation of hyaluronic acid on atmospheric pressure plasma modified polystyrene Soft Matter, 2011, 7, 608-617.

3. Fraser, J.R.E.; and Laurent, T.C. in Extracellular matrix, volume 2: Molecular components and interactions, ed. C. W.D., Harwood Academic Publishers, The Netherlands, 1996, pp. 141-199.

36  

P3: Study of physical properties and photocatalytic activity of zinc titanate

M. Kralova1, C. Guillard2, E. Puzenat2, J. Cihlar1

1 Central European Institute of Technology, Brno University of Technology, Technická

3058/10, 616 00 Brno, Czech Republic (marcela.cerna@ceitec.vutbr.cz) 2 Institut de Recherches sur la Catalyse et l’Environnement de Lyon, CNRS UMR 5256,

Universite de Lyon, 2 Avenue Albert Einstein, Villeurbanne F-69622 cedex, France A series of zinc titanate photocatalyst powders was successfully synthesized by sol-gel method and consequently by solid state reaction. Titanium(IV)isopropoxide and zinc acetate were applied as a precursors. Ethylene glycol and isopropoxide were used as a solvents and acetylacetone as a stabilizer.[1] Solid state reaction was performed at three different temperatures (700°C; 800°C, 900°C) and three different times (1h, 2h, 4h). The influence of synthesizes conditions was investigated. The crystallite phases were studied by X-ray diffraction (Rigaku) using Cu K ( = 1.5406 Å) radiation in the scan range from 2 from 15°to 100°. In all cases we observed peaks for ZnTiO3 however in some cases together with Zn2TiO4 impurity. Thermal decomposition as well as crystallization characteristics of ZnTiO3 powders was examined by thermogravimetric analysis. The band gap energy of all samples was evaluated from diffused reflection spectra. The specific surface area (BET) was estimated form the N2 adsorption/desorption method. The morphology of prepared zinc titanate powders was investigated by scanning electron microscopy (SEM). For determination of Zn:Ti ratio was applied X-ray energy dispersive spectroscopy (EDS). The photocatalytic activity of ZnTiO3 powders was evaluated as a degradation rate of formic acid. High performance liquid chromatography (HPLC) was used for the evaluation. Formic acid was chosen because of direct mineralisation to water and CO2 without creation of any stable intermediate species.[2] Moreover, formic acid also represents a possible final step in the photodegradation of more complex organic compounds.[3] The influence of different synthesis conditions was studied. The highest activity had sample prepared at 800 °C for 4 hours. Its activity was more than twice better than activity of standard (commercial pure ZnTiO3). Authors thank the Ministry of Education, Youth and Sport of Czech Republic for support by project This work was supported by the project ‘‘CEITEC-Central European Institute of Technology’’ CZ.1.05/1.1.00/02.0068 and CZ.1.07/2.3.00/30.0005 from European Regional Development Fund and by the Czech Ministry of Education under the grants LD12004.

References

[1] J. Z. Kong, A. D. Li, H. F. Zhai, H. Li, Q. Y. Yan, J. Ma, D. Wu, Journal of Hazardous Materials 171 (2009) 918–923.

[2] R. W. Matthews, Water Research, 24 (1990) 653–660. [3] M. Mrowetz, E. Selli. Journal of Photochemistry and Photobiology A: Chemistry, 180

(2006) 15–22.

37  

P4: Facile method for fabrication of TiO2 films for underwater superoleophobic applications

M.A.Gondal1, M.S.Sadullah1, D.Panchanathan2, G.H. McKinley2, K.K.Varanasi2

1Laser Research Group, Physics Department and Center of Excellence in

Nanotechnology(CENT), King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia

2Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge MA, 02139-4307 United States

In recent years, the interfacial phenomena on surfaces having novel microstructures and exhibiting extreme wettability properties like superhydrophobic and superhydrophilic have been investigated extensively. These surfaces were studied for their wide spread applications such as self-cleaning surfaces, anti-fouling, and water resistant coatings for electronic devices, especially for future solar applications. TiO2 is well known semiconducting metal oxide photocatalyst and has been applied for the decomposition of organic contaminants under UV light exposure. In addition, in term of adhesion, TiO2 based superhydrophobic surfaces exhibit a unique wettability switching from superhydrophobic to superhydrophilic under UV light irradiation. The Combination of the interesting wetting behaviour and photocatalytic property of TiO2 has given rise to its many promising applications. Here we report a facile fabrication method for robust TiO2 films using self developed spray coating deposition setup and dispersion of TiO2 nanoparticles in ethanol. The structural morphology of the synthesized surfaces was examined using scanning electron microscope (SEM). The water contact angle was measured under air and oil environment to examine the surface wettability of water. Similarly, the oil contact angle was also measured in air and water environment. We found that the TiO2 surfaces are both superhydrophilic and superoleophilic in air environment with contact angle (ca) = 0o, but superoleophobic in water environment with contact angle (ca) = 159o. Based on this interesting finding, it is worth investigating to use the TiO2 based underwater superoleophobic surfaces for novel application such as oil water separation.

38  

P5: Superhydrophilic ceramic glazes for sanitary ware

Franziska Knies1 2, Christos Aneziris2, Ludwig Gauckler3, Werner Fischer4, Thomas

Graule1

1 EMPA – Swiss Federal Laboratories for Materials Science and Technology, Laboratory for High Performance Ceramics, Switzerland

2 TU Bergakademie Freiberg, Institute for Ceramics, Glass and Building Materials, Germany

3 ETH – Swiss Federal Institute of Technology, Switzerland 4 Laufen Bathrooms AG, Switzerland

Email: Franziska.Knies@empa.ch

According to the Swiss Federal Statistical Office, a Swiss family spends an average of 7 h a week on cleaning. Due to hygienic standards especially the bathroom is in the focus of cleaning and improved cleaning procedures. For this purpose sol-gel coatings have been developed, but although they reduce contamination of sanitary ware and ease the cleaning based on hydrophilic effects, their durability to cleaning agents is modest. A new approach is the development of a ceramic glaze, which is super- even to avoid contamination in the first place, but is also super hydrophilic; thereby water can easily wash the dirt away. To achieve such surfaces, the composition of the industrially provided glazes is modified with photo-catalytically active oxides. For a partial replacement of the crystallizing agent with the photo-catalytically active oxides the AFM measurements show a lowering of the surface roughness from 40nm to 20nm, while adding TiO2 - a commonly used photo-catalyst for sol-gel coatings - increases the roughness up to 200 nm. With adding a fluorite-structured oxide to the glaze the wetting angle, measured with the sessile drop method, decreases from 45° to 26°. Further improvement in surface roughness (10 nm) and wetting angle (19°) can be achieved by applying an additional glaze with a low amount of TiO2. To fulfil the industrial requirements research has to be done to lower the surface roughness to less than 5 nm, the wetting angle to less than 5° and to optimize the crystallization behaviour of the glaze referring to colour, thermal expansion and mechanical resistance. The results indicate that the undertaken approach is a successful strategy towards the development of robust, self-cleaning and photo-catalytically active surfaces for sanitary applications.

39  

P6: Microstructural and photocatalytic properties of nanostructured TiO2/Au prepared by reactive magnetron

sputtering

I. Sayah1, M. Arab Pour Yazdi2, F. Schuster3, A. Aouni4, A. Billard5

1 IRTES-LERMPS/UTBM - Belfort-Montbéliard (France) 2 IRTES-LERMPS/UTBM - Belfort (France)

3 CEA/ Cross-cutting program on advanced materials - Grenoble (France) 4 ERMMM - Tanger (Morocco)

5 IRTES-LERMPS/LRC + CEA-IRTES-LERMPS - Belfort (France) Titanium dioxide is a well-known photocatalytic material with a wide range of applications such as water treatment [1], air purification [2], self-cleaning [3] and anti-microbial hygienic surfaces [4] due to its physical and chemical stability, its ability to degrade a wide range of organic pollutants, low-cost, and non-toxicity [5]. In this study, TiO2 coatings are deposited by reactive magnetron sputtering on heated quartz glass substrates (1000°C) previously covered by Au thin layer (<100 nm) at different pressures and draw distances. The morphology of the coatings is investigated as a function of deposition parameters in order to increase the film specific area. The obtained coatings were characterized by X-ray diffraction, scanning electron microscopy and by measurement of water angle contact variations. The photocatalytic activity was assessed by using the Orange G decomposition upon the UV illumination. Finally, microstructural and photocatalytic properties of the obtained coatings are compared with those of the films prepared under the same conditions but without Au thin interface layer. [1]- Fujishima, A. Hashimoto, K. Watanabe, T., Eds. BKC, Inc.: Tokyo, (2001) 176. [2]- Pichat, P. Disdier, J. Hoang-Van, C.; Mas, D. Goutailler, G.; Gaysse, C. Catalysis Today, 63(2000) 363. [3]- R. Wang, K. Hashimoto, A. Fujishima, M. Chikuni, E. Kojima, A. Kitamura, M.Shimohigoshi and T. Watanabe. Nature; 388 (1997) 431. [4]- Liang Zhang, Xue Bai, Hua Tian, Lvling Zhong, Cailian Ma, Yuanzhen Zhou, Shuangli Chen, Dongliang Li. Carbohydrate Polym,89 ( 2012) 1060 . [5]- K. Nakata, A. Fujishima, J. Photochem. Photobiol C. Photochem 13 (2012) 169.

40  

P7: Surface disinfection using photocatalytic coatings Ashlene Vennard*, Patrick S.M. Dunlop1, Jeremy W.J. Hamilton1, Changseok Han2, Dion

D. Dionysiou2, J. Anthony Byrne1

1 Nanotechnology and Integrated Bioengineering Centre (NIBEC), University of Ulster,

Shore Road, Newtownabbey BT37 0QB, Northern Ireland, UK 2 Environmental Engineering and Science Program School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, OH 45221-0012, USA

*Email: Clarke-a2@email.ulster.ac.uk Contaminated areas, including environmental surfaces and medical devices, are thought to play a part in the spread of pathogens throughout the hospital, either directly or indirectly via the hands of healthcare professionals1. As such, there is a need for new or complimentary methods of disinfection to combat the on-going problem of health care associated infections (HCAI). Photocatalytic coatings have significant potential to decontaminate surfaces and/or medical devices and help break the cycle of infection. Titanium dioxide (TiO2) is the most commonly employed photocatalyst for water, air and surface decontamination. TiO2 is a semiconductor with a band gap energy of 3.2eV and when irradiated with UV light ( < 385nm for anatase) produces an electron/hole (e-/h+) pair caused by the transfer of electrons from the valence band to the conduction band. The e-/h+ pair react with adsorbed water and oxygen to form highly reactive oxygen species (ROS) such as hydroxyl radicals, superoxide anion and singlet oxygen. These ROS cause damage to the bacterial cells leading to cell death via lipid peroxidation2. Recently, research has been directed towards creating visible light activated (VLA) photocatalysts which could be activated by ambient indoor light. For TiO2 to be activated by visible light the absorption spectrum of TiO2 must be shifted towards the visible region of the electromagnetic spectrum. This can be achieved through “doping” the TiO2 with non-metallic elements such as nitrogen, sulphur and fluorine. The resultant band gap narrowing is achieved through the introduction of new localised states active within the band gap3. Doping with metallic elements such as silver may also extend the visible response of TiO2 to the visible region4. A variety of photocatalysts, made by different methods, have been characterised and tested for their bactericidal efficiency. Using our microbiology testing methods1 we have shown that, in agreement with others, TiO2 when activated with UVA light results in complete bacterial kill after 90 minutes and is more efficient than UVA light alone. Our experiments on visible light active coatings show that S-TiO2 has a significant killing effect on E. coli after 120 minutes visible light illumination. Further investigation into the S-TiO2 is ongoing to determine the origin of its apparent visible light activity and the mechanism of disinfection. ______________ References: 1. P.S.M Dunlop, C.P. Sheeran, J.A. Byrne, M.A.S. McMahon, M.A. Boyle, K.G. McGuigan, J. Photochem. Photobiol., A., 2010, 216, 303. 2. O. Dalrymple, E. Stefanakos, and M. Trotz, M. Goswami, Appl. Catal., B., 2010, 98, 27. 3. C. Di Valentin, E. Finazzi, G. Pacchioni, A. Selloni, S. Livraghi, M Paganini, E. Giamello. Chem. Phys. 2007, 339, 44. 4. M. Seery, R. George, P. Floris, S. Pillai, 2007, 189, 258.

41  

P8: Antimicrobial activity of printed hybrid titania/silica transparent layers

M. Veselý1, P. Dzik1, M. Veselá1, U. Lavrenčič Štangar2

1 Brno University of Technology, Faculty of Chemistry, Purkynova 118, 612 00 Brno,

Czech Republic 2 University of Nova Gorica, Laboratory for Environmental Research, Vipavska cesta 13,

5000 Nova Gorica, Slovenia Stable mixed dispersion of nanocrystalline TiO2 and amorphous SiO2 was developed and hybrid TiO2/SiO2 layers were fabricated by the direct inkjet patterning technique. Silica serves as a binder which will cement the titania nanoparticles together and provide necessary adhesion to the substrate surface at the same time. Ideally, such binder should preferably not significantly decrease the antimicrobial activity of TiO2. The printed transparent TiO2/SiO2 layers from 40 to 160 nm thick were studied. The antimicrobial and antifungal activity of prepared printed layers were tested and evaluated by both the traditional plate count method and by a fluorescent staining method with direct enumeration of cells. An acridine orange solution was used for staining of yeasts Candida glabrata, whereas a SYTO 9 with proipidium iodide for bacteria Escherichia coli staining was used. Acridine orange is a cell-permeable dye. Live cells are coloured green, dead cells are red. Membrane-penetrating SYTO®9 labels live bacteria with green fluorescence; damaged membrane-penetrating propidium iodide labels membrane-compromised bacteria with red fluorescence. A random selection of 20 places on each sample was recorded. On each image, the number of live and dead cells was calculated and expressed as the survival ratio, i.e. number of live cells divided by total number of cells in each image. The obtained survival ratio was averaged and processed by statistical methods. This method is fast enough, but the standardization of the whole process is required. Classical plate count method is technically simple, sensitive and capable of reliable detection of defined microorganisms. Their principal drawback is that they are labour-intensive and time-consuming. Photocatalyst antimicrobial activity was tested and calculated according to ISO standard 27447 using both bacteria and yeasts. The survival ratio from plate count results was also calculated.

42  

P9: Photocatalytic water splitting by anatase-brookite biphasic nanoparticles

Vit Kasparek, Klara Castkova, Jaroslav Cihlar

Central European Institute of Technology - Brno University of Technology, Technicka

3058/10, Brno, Czech Republic, vit.kasparek@ceitec.vutbr.cz

Biphasic titania nanoparticles containing anatase and brookite were prepared by the sol-gel low-temperature reaction of titanium tetraisopropoxide with aqueous solutions of organic acids (citric acid, lactic acid, tartaric acid, glycine). Reaction was carried out at pH 4 and 100 °C for 10 hours. XRD analysis revealed that the weight ratio of anatase/brookite depended on the type of organic acid. Nanoparticles contained anatase crystallites ranging in size from 4.2 to 5.6 nm and brookite nanoparticles formed by crystallites of a size from 3.2 to 5.4 nm. Specific surface area of titanias ranged from 230-240 m2/g. All titania samples were calcined at 600 °C for 90 min. Differential photocatalytic activity of titania nanoparticles was studied at photocatalytic water splitting (of 20% aqueous solution of methanol) in batch quartz reactor in which flowed through argon. The hydrogen content in the gas phase was measured by mass spectrometer. Co-catalyst, 0.5% of Pt was deposited on the surface of titania by photochemical method. It was found that the photocatalytic activity increased with the content of brookite in a biphasic catalyst. The highest photoactivity (98.6 mol H2/min·g) had titania with the highest content of brookite (46%) prepared in the presence of lactic acid. Followed titania prepared in the presence of glycine containing 26% brookite (81.6 mol H2/min·g) and then titania prepared in the presence of tartaric acid containing 15% brookite. Lowest photoactivity had titanium oxide containing 12% brookite prepared in the presence of citric acid. Photocatalytic activity of titania biphase catalysts prepared at 600 °C increased in the same order as the activity of titania prepared at 100 °C. This work was supported by the project “CEITEC - Central European Institute of Technology” (CZ.1.05/1.1.00/02.0068) from European Regional Development Fund and by the Czech Ministry of Education under the COST grant LD12004.

43  

P10: Superhydrophilic behaviour of TiO2 nanotubes M. Radecka1, A. Wnuk1, A. Trenczek-Zajac1, K. Zakrzewska2

1AGH University of Science and Technology, Faculty of Materials Science and Ceramics,

al. A. Mickiewicza 30, 30-059 Krakow, Poland 2AGH University of Science and Technology, Faculty of Computer Science, Electronics

and Telecommunications, al. A. Mickiewicza 30, 30-059 Krakow, Poland

Titanium dioxide is commonly known as a very useful, non-toxic, environmentally friendly and corrosion-resistant material. These features constantly attract significant scientific and technological interest and make TiO2 one of the compounds the most thoroughly studied in the materials science. Moreover, superhydrophilic behaviour can be induced by illumination of TiO2 surface with the UV light. It allows obtaining commercial products with antifogging and self-cleaning surfaces. The aim of this work was to investigate the effect of anodization parameters (time and voltage) on the morphology and surface wettability of TiO2 nanotubes fabricated in solutions of two different types: the first one consisting of ethylene glycol electrolyte with varying concentration of NH4F 0.1-1.0 wt% while the second was composed of glycerol and ethylene glycol mixture with addition of NH4F 1.0-5.0 wt%. TiO2 nanotubes were grown by electrochemical anodization of a titanium foil in the DC voltage range of 20-50 V. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoelectrochemical measurements were performed in order to investigate the crystallographic structure, morphology, I-V and C-V characteristics of photoanodes based on TiO2 nanotubes. Water contact angle measurements were carried out for the control of the surface wettability before and after UV radiation. As-prepared nanotubes were found to be amorphous; however, subsequent 2-hours annealing in argon atmosphere at 450oC transformed them into the anatase/rutile phase. SEM images revealed that TiO2 nanotubes obtained in both electrolytes were ordered and uniform. Surface morphology, average diameter and length of nanotubes were affected by the parameters of the process of electrochemical anodization as well as the electrolyte composition. The superhydrophilic behaviour as the effect of the UV radiation, presented on the figure below, was observed.

The project was financed from the National Science Centre (NCN) based on the decision number DEC-2012/07/B/ST8/03879. A.W. was partially supported by the „DOCTUS”

44  

P11: Effect of QDs sensitization on the photoelectrochemical behaviour of TiO2 flower-like

nanostructures A. Kusior1, M. Radecka1, A. Trenczek-Zajac1, A. Lacz1, K. Zazakowny1, K. Zakrzewska2

1 AGH University of Science and Technology, Faculty of Materials Science and Ceramics,

al. A. Mickiewicza 30, 30-059 Krakow, Poland 2 AGH University of Science and Technology, Faculty of Computer Science, Electronics

and Telecommunications, al. A. Mickiewicza 30, 30-059 Krakow, Poland Much attention has been recently paid to the application of nanostructures to energy conversion in the photo-electrochemical cells (PEC) in order to produce hydrogen [1,2]. The growing interest in the influence of modification with quantum dots QDs of narrow-band gap semiconductor such as PbS or Ag2O upon the properties of nanostructures been observed as well. The aim of the present study was to investigate the effect of modification of TiO2 flower-like nanostructures with cadmium sulfide QDs. Nanoflowers were obtained in the oxidation process of Ti-foil (99.7%) in 30% H2O2 at 80ºC with the immersion time varied from 15 minutes to 4 hours subsequently annealed at 600ºC in Ar atmosphere. Afterwards, the QDs were deposited by a simple SILAR route [3] with the salts of different concentrations used as precursors. As-prepared and QDs-modified flower-like nanostructures were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical spectrophotometry. Measurements of the photocurrent versus voltage and wavelength over the UV and visible ranges of the light spectrum were performed. It was concluded that the rutile/anatase ratio was affected by the time of immersion. In the case of flower-like nanostructures modified with QDs it was found that the parameters of SILAR process influenced both a distribution of QDs and the current-voltage characteristics measured in the PEC.

The project was financed from the National Science Centre (NCN) based on the decision number DEC-2011/01/D/ST5/05859. A.K. was partially supported by “DOCTUS – Malopolski Fundusz Stypendialny dla Doktorantow”. [1] J. Qiu, M. Guo, Y. Feng, X. Wang, Electrochimica Acta, 56/16, 5776 (2011). [2] S.S. Mali, R.S. Devan, Y.-R. Ma, C.A. Betty et al., Electrochimica Acta, 90, 666 (2013). [3] S. Rule, M. Shalom, A. Zaban, Chem Phys Chem, 11, 2290 (2010).

45  

P12: Putting theory into practice: monitoring photoactive surfaces on a Manchester wall

A Scimone, J Verran, PJ Kelly

Manchester Metropolitan University, Manchester, UK

Photoactive coatings have been well-characterised in laboratory settings, but fewer data are available that describe performance in outdoor trials, particularly over long time periods. In this study, a range of titanium dioxide coatings will be trialled, being applied to different substrates on a west-facing wall of a 1970’s building in central Manchester. Tests to determine self-cleaning capacity, antimicrobial properties and NOx abatement will be carried out over a 12 month period. The display will also be used as a vehicle for informing the public about photocatalysis, sustainability, and some of the research activities current in the University. Glass, stainless steel, concrete, and brickwork were used as test substrates, being coated with TiO2 in paint, sol-gel and thin film (via physical vapour deposition) formats. Assessments of performance will be made regularly over a 12 month period: self-cleaning on opaque surfaces (relative reflection), and transparent (relative transmission) surfaces. NOx abatement will be assessed by comparing initial level photocatalytic activity of sensitive paint-coated films to activity on a monthly basis; reduction in activity indicates NOx has been adsorbed and subsequently oxidised. Antimicrobial activity of photoactive glass, stainless steel and painted stone surfaces will be investigated by swabbing, culture, and count methods for bacteria and fungi. Results will be reported on a two-monthly basis for one year.

46  

P13: Preparation of superamphiphobic surfaces on titanium substrates

Yao Lu1, Jinlong Song2, Wenji Xu2, Ivan P. Parkin1*

1. Department of Chemistry, University College London, 20 Gordon Street, London,

WC1H 0AJ, UK 2. Key Laboratory for Precision and Non-traditional Machining Technology for Ministry of

Education, Dalian University of Technology, Dalian, 116024, People’s Republic of China

Many natural surfaces such as plant leaves and the legs of a water strider are superhydrophobic. These surfaces display a water contact angle greater than 150o. The lotus effect is a well-known property of superhydrophobic surfaces that results in self-cleaning due to the rolling of water droplets on the surface. However, liquids with lower surface tensions, such as hexadecane, rapidly spread across the lotus leaf, leading to a contact angle of nearly 0°. In addition, the oleophilicity may lead to the loss of the self-cleaning ability of superhydrophobic surfaces in polluted water. Thus, superamphiphobic surfaces, which repel both water and oil, have considerable potential values in fundamental research and industrial applications, such as in understanding the wetting behaviour, oil transfer, and self-cleaning in oily conditions. The preparation of superamphiphobic surfaces requires surface microgeometries and surface chemistry. Here, we present an economical and environmentally friendly electrochemical etching method to prepare superamphiphobic surfaces on titanium substrates. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrophotometry (FTIR), energy-dispersive spectroscopy (EDS), and optical contact angle measurements were used to characterize the surface morphologies, crystal structures, chemical compositions, and wettability of the surfaces for both water and oil. The results show that the prepared superamphiphobic surface has water, glycerol, and hexadecane contact angles above 150°, with rolling angles of only 1−2°. Analysis of the electrolyte, the reaction process, and the products demonstrates that the proposed method is inexpensive and environmentally friendly. The effects of electrochemical parameters such as current density, electrochemical etching time, electrolyte temperature, and electrolyte concentration on the surface wettability for water, glycerol, and hexadecane were also investigated. Wettability for water and oil can be selectively obtained by varying the electrochemical parameters. The proposed method is believed to be adopted for industrial production of superamphiphobic surfaces on titanium substrates.

47  

P14: TiO2 – based photocatalytic oxidation of Paracetamol

Aboel-Magd A. Abdel-Wahab1*, El-Sayed A. Al-Shirbini2, Omima S. Mohamed1 and Osama A. Nasr1

1

Chemistry Department, Faculty of Science, Assiut University, Assiut, 71516, Egypt 2 National Institute of Laser Enhanced Sciences, Cairo University, Cairo, Egypt

* Corresponding author e.mail: wahab_47@hotmail.com

In addition to the industrial and agricultural contaminants, many pharmaceutical compounds and their metabolites have been detected in the last decades as pollutants in industrial wastes, surface and ground water. Several advanced oxidation processes (O3, O3 / H2O2, H2O2 / UV, H2O2 / Fe+2/ UV, TiO2 / UV) 1, 2 have been reported for destruction of pollutants via the reactive ·OH intermediates. Paracetamol (PAM) is a non-steroidal anti-inflammatory (NSAID) common house hold drug, also known as acetaminophen, 4-hydroxyacetanilide and 4-actamidphenol. It is a widely used aniline analgesic, antipyretic and a main constituent for several formulas such as Tylenol. The application of TiO2 based photocatalysis, the main target of the present work, aims at search for more simple and efficient method for destruction of such pollutant in addition to understanding the operating mechanism. In continuation to our interest on photocatalytic oxidation (PCO) of organic compounds3, the present work deals with PCO of PAM as a widely used drug. The study includes effect of light source, type and size of catalyst, as well as other different operating parameters on the photocatalytic oxidation process. References: 1- E. Moctezoma, E.Leyava, C. A. Aguilar, R. A. Luna and C. Montalova, J. Hazardous

Materials, 243, 130-138 (2012).

2- I. Dalmazio, T. M. A. Alves and R. Augusti J. Braz. Chem. Soc., 19 (1), 81-88 (2008).

3- A.A. Abdel-Wahab, O. S. Mohamed, S. A. Ahmed and M.F. Mostafa, J. Phys. Org. Chem., 25, 1418-1421 (2012).

48  

P15: Low temperature deposition method for producing transparent and photocatalytically active TiO2 layers

Watté J., Arin M., Lommens P., Van Driessche I.

SCRiPTs, Department of Inorganic and Physical Chemistry, Ghent University, Belgium Krijgslaan 281 (S3), 9000 Ghent, Belgium

Jonathan.Watte@UGent.be http://www.we06.ugent.be/

Transparent and photocatalytically active TiO2 coatings have a very high industrial relevance as they exhibit self-cleaning, antifogging and superhydrophilic properties. Therefore it is important to develop cheap, fast and environmentally friendly deposition techniques in line with industrial demands for large scale applications. In order to obtain functional layers, crystallization of this material is necessary at temperatures above 400°C. As most state-of-the-art deposition approaches such as chemical vapor deposition or sol-gel deposition do not allow deposition on heat sensitive substrates such as polymers. Therefore, it is necessary to investigate innovative deposition processes that can significantly reduce the minimal temperature required for crystallization and full processing.

Enabling the deposition of TiO2 coatings on polymers by a wet chemical deposition approach, might initiate an entire new range of applications. Therefore, we studied the synthesis of crystalline titania nanoparticles by microwave-assisted hydrothermal treatment. The use of microwaves allows us to optimize the production and energy efficiency of the synthetic process. The fact that the crystalline building blocks for the layer are now already present in the precursor inks, allows efficient deposition of transparent TiO2 coatings at reduced temperatures. However, this water-based approach shows some important deficiencies i.e. low conversion rates and crystallinity of the synthesized nanoparticles and color defects in the TiO2 films due to the presence of alcoholamines and unreacted Ti-alkoxides. Therefore, a transfer to organic solvents has been made in which hydrolysis reactions are suppressed and thus there is less need of complexing reagents to inhibit hydrolysis and uncontrolled reactions. Based on this knowledge, Ti4+-precursors with a low organic content which provide highly crystalline titania suspensions are being developed.

Figure 1: TEM image collected of a TiO2 nanoparticle-containing suspension.

Research funded by EU project EFECTS (FP7-NMP-2007-SMALL-1 grant n°205854).

49  

P16: Photoinduced pollutant removal using nanostructured TiO2 thin films

V. Likodimos1, A.G. Kontos1, G.Em. Romanos1, C. Han2, M. Pelaez2, D.D. Dionysiou2, P. Falaras1*

1Division of Physical Chemistry, Institute of Advanced Materials, Physicochemical Processes, Nanotechnology & Microsystems, NCSR “Demokritos”, 15310, Aghia

Paraskevi Attikis, Athens, Greece 2Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH

45221-0012, USA

Titanium dioxide (titania, TiO2) nanostructured thin films present interesting photoinduced catalytic and superhydrophilic properties that can find extremely useful applications in environmental cleaning and health protection. During the last years special emphasis is paid to the removal of pollutants in both water and air as well as to the development of self-cleaning and self-sterilizing surfaces [1-4]. For these applications the structural (anatase, rutile, brukite), morphological (nanoparticles, nanotubes) and optoelectronic properties of titania-based nanomaterials are under intensive investigation. Fine tuning of the preparation conditions, selection of adequate deposition techniques (dip-coating, screen-printing, anodization) and detailed characterization using state of the art microscopic and spectroscopic techniques permit the tailoring of the properties of TiO2 films at the nanoscale as well as the effective control of their porosity, particle size, real surface area, roughness and complexity.

To these directions, highly efficient nanocrystalline TiO2 thin film photocatalysts were developed, able to decompose virtually a broad range of pollutants in water, air, soil and surfaces [5]. These innovative titania photocatalysts comprise metal and non-metal doped TiO2 nanomaterials, nanocarbon-TiO2 composites (carbon nanotubes, reduced grapheme oxide), TiO2–modified porous fibers, and photocatalytic nanofiltration membranes. The materials exhibit high photocatalytic activity and their incorporation in nanotechnology-based photoreactors and functional substrates were used with great success for water treatment, air purification, and self-cleaning surfaces.

Intensive current research activity in the field focuses on the development of visible light active-titania materials, the simultaneous existence and optimization of photocatalytic and superhydrophilic properties on the same surface, the elucidation of the nature of reactive oxygen species mechanism in the presence of visible light and the answer to fundamental questions concerning visible light ability to create hydroxyl radicals and/or induce superhydrophilic effects, without excluding coordinated efforts for the scale-up of both materials and processes for several practical applications [6].

In this presentation, the results of characterization of TiO2-based nanomaterials synthesized by finely-tuned preparation methods and their photocatalytic and superhydrophilic properties for the removal of water and air contaminants will be discussed in detail. 1. A. I. Kontos, A. G. Kontos, D. S. Tsoukleris, G. D. Vlachos, P. Falaras, Thin Solid Films, 515 (2007) 7370-7375. 2. T. Maggos, A. Katsanaki, C. Vasilakos, A.G. Kontos, P. Falaras, WIT Transactions on Ecology and the Environment, 157 (2012) 489-500. 3. A. Katsanaki, A.G. Kontos, T. Maggos, M. Pelaez, V. Likodimos, E.A. Pavlatou, D.D. Dionysiou, P. Falaras, Applied Catalysis B: Environmental, 140–141(2013) 619–625. 4. A.G. Kontos, A. Katsanaki, T. Maggos, V. Likodimos, A. Ghicov, D. Kim, J. Kunze, C. Vasilakos, P. Schmuki, P. Falaras, Chemical Physics Letters 490 (2010) 58–62. 5. V. Likodimos, D.D. Dionysiou, P. Falaras. Reviews in Environmental Science and Bio/Technology: 9 (2010) 87-94. 6. M. Pelaez, N. Nolan, S.C. Pillai, M. Seery, P. Falaras, A.G. Kontos, P.S.M. Dunlop, J.A. Byrne, K. O’shea, M.H. Entezari, D.D. Dionysiou, Applied Catalysis B: Environmental, 125, 331 (2012).

50  

P17: Visible light active titania thin film photocatalysts

V. Likodimos1, D.D. Dionysiou2 and P. Falaras1*

1Division of Physical Chemistry, Institute of Advanced Materials, Physicochemical Processes, Nanotechnology & Microsystems, NCSR “Demokritos”, 15310, Aghia

Paraskevi Attikis, Athens, Greece 2Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH

45221-0012, USA

Titanium dioxide (TiO2) photocatalysis has emerged as a promising advanced oxidation technology for the destruction of most hazardous pollutants in water and air as well as pathogenic microorganisms, attracting particular interest for self-cleaning, antimicrobial and air purification applications. However, despite the marked progress in the development of TiO2 photocatalytic materials, their practical application is challenged by the wide band gap of all TiO2 polymorphs (3.0-3.2 eV) that limits titania’s response essentially to the UV range (4-5% of the solar spectrum) and the fast recombination of photo-generated charge carriers. Intensive research efforts have been accordingly devoted to alleviate electron-hole recombination and improve the light harvesting ability of TiO2 in the visible range [1] that would enable the realization of an essentially “green” environmental technology. In this contribution, the development of visible light-activated TiO2 photocatalysts and their efficiency for the photodegradation of water (cyanotoxins) and air (nitrogen oxides-NOx) pollutants as well as their superhydrophilic properties under visible light will be presented. Mesoporous anion doped TiO2 thin films and particles were synthesized by modified sol-gel methods based on the self-assembly technique to improve simultaneously the structural, morphological and electronic properties of TiO2 nanomaterials. Extensive physicochemical characterization of the materials properties verified that hydrocarbon surfactants in combination with suitable precursors can simultaneously tailor the structural properties of TiO2 and extend titania’s light harvesting in the visible range by doping with N-F, S, and C species. The anion doped TiO2 materials immobilized in the form of nanostructured films on glass substrates exhibited high efficiency for the photodegradation of the microcystin-LR cyanotoxin, a hazardous water pollutant of emerging concern, and the photodecomposition of NOx in air together with a slow hydrophilic conversion under visible light illumination. The development of these visible light-activated TiO2 films may provide environmentally benign routes for photocatalytic coating applications. [1] Pelaez M., Nolan N., Pillai S.C., Seery M., Falaras P., Kontos A.G., Dunlop P.S.M., Byrne J.A., O’Shea K., Entezari M.H. and Dionysiou D.D., Applied Catalysis B: Environmental, 125, 331 (2012), review paper.

51  

P18: Production of self-cleaning cement containing modified titanium dioxide

M. Janus1, J. Zatorska2, K. Bubacz2, E. Kusiak – Nejman2, A. Czyżewski2,

A. W. Morawski2

1 West Pomerania University of Technology, Department of Sanitary Engineering, Piastów

50, 70-310 Szczecin, Poland 2 West Pomerania University of Technology, Szczecin, Institute of Chemical and

Environmental Engineering, Pułaskiego 10, 70-322 Szczecin, Poland The photocatalytic activities of cements, containing various amounts of co – modified titanium dioxide (TiO2) were evaluated through the degradation of organic compound. The starting TiO2 supplied from the Chemical Factory “POLICE” S.A. (Poland) was modified by nitrogen and carbon at 600 °C for 1.5 h. The source of nitrogen and carbon in the co – modified TiO2 was ammonia gas and methanol, respectively. The samples were prepared with different additions of TiO2 from 1% up to 20% w/w (the modified photocatalysts, reference material – commercial P 25 Evonik) in the mixtures with Portland cement. The photocatalytic properties of the samples were studied through the degradation of Reactive Red 198 dye. The rate of degradation was determined by UV-Vis/DR spectroscopy. The self-cleaning ability of the prepared cement samples were evaluated in a photocatalytic activity test under both UV-Vis and Vis irradiation. It was observed that the prepared cement samples with addition of co-modified TiO2-N,C are able to clean their surfaces. Moreover, the rate of dye photocatalytic degradation was increasing with the content of TiO2 in mixture with cement. It ought to be stated that the cement sample with commercial P25 revealed significantly lower removal rate of RR 198 than the prepared one. Acknowledgement: Project was founded by The National Centre for Research and Development, LIDER III program

52  

P19: Photocatalytic discoloration of organic dye on building gypsum plasters containing co-modified TiO2-N,C under UV or

Vis irradiation

M. Janus1, K. Bubacz2, J. Zatorska2, E. Kusiak – Nejman2, A. Czyżewski2, A. W. Morawski2

1 West Pomeranian University of Technology, Szczecin, Department of Sanitary

Engineering, Piastów 50, 70-310 Szczecin, Poland 2 West Pomeranian University of Technology, Szczecin, Institute of Chemical and

Environmental Engineering, Pułaskiego 10, 70-322 Szczecin, Poland Gypsum-based plasters are one the most usual interior coating of walls and ceilings of buildings [1]. Apart from good acoustic performance or fireproof features it is worth enhancing self-cleaning properties of these materials. Coupling gypsum with photocatalyst TiO2 seemed to be a good solution. Especially, in order to broaden Vis response of the semiconductor, the modification with non-metal ion was taken into account.

In the study gypsum were mechanically mixed with the prepared TiO2-N,C photocatalysts in 10% weight ratio (starting TiO2 material originates from Chemical Factory “POLICE” S.A. in Poland). Titanium dioxide was modified by nitrogen (ammonia gas) and carbon (ethanol) at 100, 300, 400, 500 and 600 °C for 1.5 h. Self – cleaning properties were studied on the basis of Reactive Red 198 dye removal. Gypsum plasters containing prepared photocatalysts exhibited photocatalytic properties under both UV and Vis irradiation (Fig. 1). The photoactivity was also affected by calcinations temperature applied during preparation of the photocatalysts, achieving the highest removal rate using gypsum plaster with TiO2-N,C – 300 °C under both irradiation sources.

Figure 1. Photocatalytic degradation of Reactive Red 198 on gypsum plasters with addition of TiO2-N, C photocatalysts modified at different temperatures: a) UV, b) Vis irradiation.

Acknowledgement: Project was founded by The National Centre for Research and Development, LIDER III program. Reference: [1] A. Pereira, F. Palha, J. de Brito, J.D. Silvestre, Inspection and diagnosis system for gypsum plasters in partition walls and ceilings, Construction and Building Materials 25 (2011) 2146–2156.

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53  

P20: Preparation of visible light-active TiO2 by thermal modification with naphthalene

Ewelina Kusiak-Nejman, Agnieszka M. Wanag, łukasz Kowalczyk, Joanna Kapica, Antoni

W. Morawski West Pomeranian University of Technology, Szczecin, Institute of Chemical and

Environment Engineering, Pułaskiego 10, 70-322 Szczecin, Poland (Ewelina.Kusiak@zut.edu.pl)

Many researchers have been focused on carbon modification of TiO2 due to the enhancement of photocatalytic activity under visible light irradiation. One of that kind of modification is the thermal modification of starting titania by carbon from different organic precursors (sucrose [1], glucose [2], aliphatic alcohols [3]).

In this study calcination of TiO2 obtained by the sulphate technology in Chemical Plant “Police” S.A (Poland) in naphthalene atmosphere in a tubular furnace at 150-450°C (∆t=100°C) for 4 hours was conducted to prepare TiO2/C nanomaterials. The photocatalytic activity of tested materials was determined on the basis of phenol solution decomposition under UV-vis light irradiation with low UV intensity (0.26 W/m2 UV and 720.6 W/m2 Vis).

On basis of UV-vis/DR analysis it was possible to find insignificant changes in band gap energy but it was also noted that calcination of starting TiO2 with naphthalene leads to improve absorption in visible range. It could be explained by changes in photocatalysts colour from white for starting titania and grayish brown for carbon-modified TiO2. Enhancement of the activity of tested TiO2/C photocatalysts increased with modification temperature. This could be related to carbon content because the higher calcination temperature the higher amount of carbon in tested samples.

Figure 1. Decomposition and mineralization rates of phenol solution for tested materials under UV-vis light irradiation with low UV intensity

References: [1] Dong F., Guo S., Wang H., Li X., Wu Z., J. Phys. Chem. C 115 (2011) 13285. [2] Lin X., Rong F., Ji X., Fu D., Micropor. Mesopor. Mat. 142 (2011) 276. [3] Kusiak-Nejman E., Janus M., Grzmil B., Morawski A., J. Photochem. Photobiol. A 226 (2011) 68. Acknowledgement: This work was supported by grant No. 506-10-011-4524/6 (National Science Centre, Poland).

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54  

P21: Influence of pH and H2O2 on tungsten oxide and fly ash mixtures for dyes removal from wastewater

M. Visa, C.Bogatu, A. Duta

Transilvania University of Brasov, Eroilor 29, 500036 Brasov, Romania,

maria.visa@unitbv.ro

The use of fly ash (FA) in wastewater treatment, for heavy metals and dyes immobilizations, represents a good application for solving the problems of advanced treatment and the intelligent use of this waste. For advanced removal of dyes even at low concentration we propose a single step involving two concurrent, simultaneous processes: photocatalysis and adsorption based on a mixture of catalysts (WO3) and fly ash (FA).

In this paper presents, dyes removal using WO3+FA is investigated in dark (adsorption) and under UV illumination (adsorption + photocatalysis) in systems containing a single dye (Bemacid Blau- BB or Bemacid Rot—BezemaAG - BR) with Cu2+ cations or mixtures of two dyes (BB+BR) and Cu2+ cations.

In this case, the effect of the heavy metals on tungsten trioxide activity, along with the parallel process involving the dyes and the fly ash must be considered.

The experimental tests were done in batch experiments, under stirring. The dye specific uptake by adsorption-photodegradation depends on the type of dye, the contact time, the initial concentration of dye, the pH value in the system, H2O2 amounts, the fly ash structure and morphology, the ratio FA-NaOH:WO3.

The adsorbent material was characterized from the point of view of topography and roughness (atomic force microscope, AFM/ Ntegra Spectra, NT-MDT model BLRNTE), structure (Bruker D8 Discover Diffractometer) and specific surface (Quantacrome specific surface equipment).

The adsorption efficiency, η, was evaluated based on the initial and equilibrium concentration of the cations and of the dyes BB and BR. Heavy metals concentration was measured using atomic absorption spectroscopy (Analytic Jena, ZEEnit 700), while the dyes quantitative analysis was done by UV-VIS spectroscopy (Perkin Elmer Lambda 25) (λmax, BB =629 nm and λmax, BR= 298 nm).

Competitive adsorption occurs between the initial components but also between these and possible by-products resulted after photocatalysis. An increase of process efficiency is obtained by adding H2O2 leading to a higher number of active species, HO.

The results prove that the FA-NaOH:WO3 system can be used for cleaning the wastewater with a complex pollutant load. In designing industrial wastewater treatment process, results obtained on single-dye solutions must be completed with data on real wastewaters.

Acknowledgment. This work was supported by a grant of the Romanian National Authority for Scientific Research, CNCS – UEFISCDI, project number PN-II-RU-TE-2012-3-0177/2013.

55  

P22: New Composites obtained by freundlich conditions for advanced wastewaters process

M. Visa, A. Duta

R&D Center Renewable Energy Systems and Recycling, Transilvania University of

Brasov, Eroilor 29, 500036, Romania

The goal of this paper was to develop a new composite at low-temperature using TiO2-modifed fly ash (TiO2-MFA), composites based on interaction in alkaline solution using hydrothermal methods, to obtained crystalline nanocomposite at room temperature without heat treatment stage.

These composites are interesting to be applied in visible photocatalysis/adsorption simultaneous advanced wastewater processes. Combining fly ash with titanium dioxide has the following advantages: (1) the titanium oxide crystallites grow on the support fly ash), (2) pollutant molecules migrate to the surface of TiO2 can be degraded by photocatalysis and (3) fly ash substrates are regenerated in situ.

The nancomposites were synthesized from Degussa P25 and fly ash activated in sodium hydroxide solutions (NaOH) at hydrothermal conditions, resulting anatase and rutile crystalline phases by controlling the content of water/solvent. The composites were characterized by the scanning electron microscopy (SEM) and atomic force microscopy (AFM) for morphological characterization of the surface, X-ray diffraction (XRD) for phase and crystallinity analysis, UV-VIS spectroscopy to calculate the energy band gap, surface analysis by determining the contact angle, porosity analysis (BET) and isoelectric point (pHzpc).

The photocatalytic property of the composites was evaluated by dyes (methyl orange), surfactant (sodium dodecyl sulphate) degradation under UV and Visible irradiation. The adsorption tests were made on heavy metal (Cu2+) anion. Properties of composites were correlated with the adsorption/photocatalytic activity of the samples.

Acknowledgments: This work was supported by a grant of the Romanian National Authority for Scientific Research, CNCS – UEFISCDI, project number PN-II-RU-TE-2012-3-0177/2013.

56  

P23: Photocatalytic activity of paints containing commercial ZnO and TiO2 photocatalysts

M.Baudys1, M. Zlámal, J. Krýsa

1 ICT Prague, Technická 5, 166 28 Prague, Czech Republic (baudysm@vscht.cz)

Photocatalytic self-cleaning paints contain besides usual pigments and fillers also particles of photocatalytic material. In the preparation of a photocatalytic paint it is important to find a compromise between maintaining a reasonable degree of photocatalytic activity and still retaining a good paint stability. Clearly, a high level of photocatalytic activity in a paint will produce a low paint lifetime due to light-induced weathering and photo-chalking. Thus the objective of this work was to determine photocatalatytic activity of paints containing commercial ZnO and TiO2 photocatalysts as a function of weathering in QUV panel. Photocatalytic activity was determined in aqueous phase using Acid Orange 7 and compared with the method based on indicator inks [1]. This method is based on the irreversible reduction of dye which is connected with color change. For example resazurin ink (blue) containing glycerol as a sacrificial electron donor and hydroxyethylcelulose as a binder is reduced to resorufin (pink). Compared to oxidative discolorization, photoreduction of resazurin is very quick process and takes few minutes [2]. As a photocatalysts were used TiO2 P25 (Degussa/Evonik), XRD (70% anatase, 30% rutile), BET surface area (50m2/g), and ZnO Zano 30 (Umicore), XRD (100% zincite), BET surface area (30m2/g). From photocatalytic activity in aqueous phase results that in the case of unexposed samples, paints containing ZnO shows higher photoactivity. After exposition in QUV panel, photoactivity of paints containing ZnO decreases, while photoactivity of paints containing TiO2 gradually increases. The decrease of photoactivity of ZnO paints is likely connected with photocorrosion [3,4] of ZnO which tends after UV irradiation to ZnO dissolution and formation of Zn2+. This assumption is in agreement of surface analysis using EDAXS EDS microprobe which shows that after QUV exposition the surface concentration of Zn decreases. On the other side the surface concentration of Ti in TiO2 paints increases which suggest that the TiO2 photocatalyst particles remain on the surface. References: [1] A. Mills, M. McGrady. J. Photochem and Photobiol A: 193 (2008) 228-236 [2] A. Mills et all J. Photochem and Photobiol A :275 (2013) 18-20 [3] L. Zhang et all J. Phys. Chem C 113 (2009) 2368-2374 [4] N. Daneshvar et al. J. Photochem and Photobiology A. 162 (2004) 317-322 Acknowledgement: This work was supported by the Ministry of Industry and Trade of the Czech Republic (MPO FR-TI4/364) and by the EU 7th Framework Programme for Research (FP7-NMP-2012-CSA-6, GA No. 319210).

57  

P24: Water disinfection strategies using solar photo catalysis and some prototype devices for small scale water purification

Naseer Ahmad1, M.A.Gondal1, Anwar Khalil Sheikh1

1 Mechanical Engineering Department, KFUPM, Dhahran, Saudi Arabia

2Physics Department, KFUPM, Dhahran, Saudi Arabia

Significant amount of research and development efforts are carried out in semiconductor photo catalysis to identify the methods for disinfection and decontamination of water while considering the sustainability and environment friendly aspects into account. Nano catalysis by solar UV radiation is one of the potential candidates for this emerging application. In this work basics of solar catalysis to produce the OH radicals by TiO2 and solar reacting system required to perform solar photo catalysis is described. Various design aspects of solar photo catalytic reactors are discussed for concentrating and non-concentrating type of collectors for the maximum collection of UV radiation (direct and diffuse) and to optimize the process efficiency. Based upon the design recommendations, stair type non-concentrating and parabolic type concentrating prototype reactors have been designed, developed and tested for their efficiency at KFUPM vicinity. In the testing of reactors, water flow rate, exposure time, irradiation, temperature are closely monitored and water samples are collected at different intervals to investigate the reactor efficiency. In this work detailed designed aspects of the reactors, process parameters and reactor efficiency will be discussed.

58  

P25: Photo-induced superhydrophilicity and underwater oil repellency of TiO2 films and their application for oil water

separation

M.S.Sadullah1, M.A.Gondal1 , D.Panchanathan2, G.H. McKinley2, K.K.Varanasi2

1Laser Research Group, Physics Department and Center of Excellence in

Nanotechnology(CENT), King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia (magondal@kfupm.edu.sa)

2Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge MA, 02139-4307 United Sates

Materials of high wettability nature are highly desired in oil industry for treatment of oily industrial wastewater and oil water separation. Oil–water separation has recently become important because of the vast use of water for recovery of oil from old oil wells by pressurizing them with water and also frequent occurrence of oil spill accidents due to the offshore oil production. Hence there is an increasing demand for the development of effective and inexpensive approaches for the oil water separation and cleaning-up of the oily pollution in water system. TiO2 is a photocatalytic material with band gap of 3.02 eV which correspond to UV spectrum. The photocatalytic activity of TiO2 is very effective in complete mineralization of organic pollutants and photo-induced superhydrophilicity under UV irradiation. Some recent studies have proven that superhydrophilic-superoleophilic surfaces have high underwater oil repellency. The oil repellency is increased even more for surfaces with hierarchical structure. Here we demonstrate a cost effective and fast method for preparation of TiO2 films using spray deposition of TiO2 nanoparticle dispersion on stainless steel mesh. The surface roughness of the films can be tuned by controlling the amount of deposited TiO2 nanoparticles on the mesh. We studied the application of these films prepared by this method for oil water separation using mixtures of oil and water using oils with different surface tension. The underwater oil repellency of the TiO2 films was greatly increased after UV irradiation. We found that the photo-induced superhydrophilicity is highly beneficial for oil water separation applications and the method adopted in this work using spray gun is very cost effective method to fabricate films having large area for industrial applications in the field. Acknowledgement: The support by KFUPM through project # R12-CW-11 (MIT11109 & MIT11110) under Center of Excellence for Scientific Collaboration with MIT is gratefully acknowledged

59  

P26: Probing the Mechanism of Visible Light Photoactivity using Photoelectrochemistry

J.A. Byrne1, J.W.J. Hamilton1*, P.S.M. Dunlop1, D.D. Dionysiou2, M. Pelaez2, K. O'Shea3,

S. C. Pillai4

1 Photocatalysis Research Group, NIBEC, University of Ulster, Newtownabbey, Northern Ireland. BT370QB

2 Environmental Engineering and Science program, University of Cincinnati, University Hall, Suite 530, Cincinnati, OH. 452210222

3 Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8TH ST, Miami, FL. 331990001

4 Department of Environmental Science, School of Science, Institute of Technology Sligo, Ash Lane, Sligo, Ireland

To improve the solar efficiency of photocatalysis doping TiO2 with non-metals represents one of the more promising approaches to yield visible light activity (VLA) although the mechanism is not fully understood. TiO2, N-TiO2 and N, F-TiO2 films were prepared on conducting substrates and the electrochemical response was analysed under polychromatic and monochromatic irradiation. Comparison of the photocurrent spectra in the absence of hole acceptors showed a strong UV response but weak response in the visible region. The addition of hole acceptors which could be oxidised by a mid-gap state showed no marked increase in the visible light photocurrent response. The addition of superoxide showed a small increase in the visible light photocurrent response. The open circuit photopotential spectra of doped samples showed a clear response across both the UV and visible regions and correlated well to the absorption spectra of the materials. In addition the maximum open circuit photopotential was reduced in the presence of oxygen indicative of scavenging. The differences in Photocurrent and photopotential spectral results are explained by a model describing internal charge transfer between defect and dopant states.