research article synthesis of high surface area mesoporous ...research article synthesis of high...

Research ArticleSynthesis of High Surface Area Mesoporous Silica Powder UsingAnionic Surfactant

Sang-wook Ui In-seok Choi and Sung-churl Choi

Division of Materials Science amp Engineering College of Engineering Hanyang University 17 Haengdang-dong Seongdong-kuSeoul 133-791 Republic of Korea

Correspondence should be addressed to Sung-churl Choi choi0505hanyangackr

Received 5 November 2013 Accepted 11 December 2013 Published 5 February 2014

Academic Editors J L C Fonseca and Y Yue

Copyright copy 2014 Sang-wook Ui et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Over the past several years synthesized mesoporous nanosilica (SiO2) powders have been developed by many different methods

The methods include precipitation and microemulsion the Stober method chemistry and technology In this study mesoporoussilica powders are synthesized by the sol-gel method The sol-gel method obtains a high purity silica powder however the processyields a low percentage Past syntheses of SiO

2powder precursors are expensive but this study needs to find a replacement precursor

for low cost alternatives A high surface area was used to form an anion surfactant sodium dodecyl sulfate which regulates themolar concentration The particles size variability was changed by the precursor molar ratio of the sodium silicate solution withhydrochloric acid

1 Introduction

The silica powders are considered competent materialsbecause of their unique characteristics such as low densitylow thermal conductivity high surface area high thermalshock resistance and high specific strength [1 2] They alsohave the potential to be used in a wide range of applicationsincluding catalysts thermal and electrical insulators adsor-bents filters light-weight structuralmaterials optoelectronicdevices humidity sensors chemical polishing and other fineprecision equipments [3ndash6] According to recent academicand technical reports various chemical methods have beendeveloped to control the particle shapes size and distributionof fine silica particles In the conventionalmethod ammonia-catalyzed reactions of tetraethylorthosilicate with water inlow-molecular-weight alcohols are synthesized by StobermethodHowever thismethod has to use a high cost alkoxideor organometallic compound In this work we demonstrate asol-gelmethod that controls the sphere size cubic shapes andmesoporous silica using the low cost sodium silicate solutionwith surfactant sodium dodecyl sulfate (SDS) The pore sizeand surface area of the silica varied with pH and aging time

The characteristics of the silica varied with the change insurface area pore volume and particle shapes

2 Experimental

21 Synthesis The flow chart in Figure 1 shows the experi-mental steps involved in the rapid processing of cubic silicapowders In a study on the typical synthesis the water glasssolution was prepared in a beaker and the 1MHCl solutiondripped for 30 minutes The mixture was stirred for 10 hourswith amagnetic bar at 400 rpmusing a churner [7]Thewaterglass solution was diluted with the desired weight percentageof silica in the starting material then washed in runningwater using a filter paper In the washing process our groupused at least 5 L of deionized water to remove Na+ ions fromthe water glass solution resulting in the formation of silicicacid and got a high purity silica powder [8] In the nextstep the displaced pore water was then removed from thebeaker and the organic-gels were dried at ambient pressurein hot air drying equipment at 80∘C This far explained thefundamental synthesis of silica powder Figure 2 shows thesecondmethod of the high surface area of nanoparticle silica

Hindawi Publishing CorporationISRN Materials ScienceVolume 2014 Article ID 834629 6 pageshttpdxdoiorg1011552014834629

2 ISRNMaterials Science

Water glass

Reactor

Filter

Acid

Gel milling

New drying

Heating

Product

Washing

Water

de-Na Na

Figure 1 Flow chart showing the processing steps for the cubic silica powder

DI water Surfactant

Mixing

Washing

Aging

Water glass

Drying

Sieving

DI water

Calcination

Figure 2 Flow chart showing the processing steps for high specific surface area of nanosilica power and spherical shape particles

The high surface area silica powder manufactured for theexperimental methods was based on experimental methodsused for pH adjustment and surfactantThe reactionmixturesfor the synthesis of high surface silica powder were preparedin beakers pH 1 to 6 solutions were prepared by addingdeionized water dropwise by a pipet The other synthesis wasperformedwith different proportions of reagents surfactantsand pH which are summarized in Table 1 Sodium dodecylsulfate (SDS) was dissolved by stirring in a mixture ofdeionized water and concentrated hydrochloric acid (HCl)The stirringwas stoppedwhen themixturewas homogenizedThe mixture was aged at 50∘C in hot air drying equipmentunder static conditions for 24 hours Precipitated gelationwasfiltered off washed with 5 L deionized water and dried at

Table 1 pH reaction condition (pH 1simpH 6)

Number WG SDS Water HCI pH1 1 003 20 02 12 1 003 20 02 23 1 003 20 02 34 1 003 20 02 45 1 003 20 02 56 1 003 20 02 6

80∘C for 10 hoursThe surfactant was removed by calcinationat 700∘C for 10 hours [9]

ISRNMaterials Science 3

500

400

300

200

100

010 20 30 40 50 60 70 80 90

2120579

Inte

nsity

(cps

)

(a)

1120583m

(b)

Figure 3 Centrifuges hot air drying machine XRD graph and SEM image

500

400

300

200

100

010 20 30 40 50 60 70 80 90

2120579

Inte

nsity

(cps

)

(a)

500nm

(b)

Figure 4 Filter paper washed and hot air drying machine

500

400

300

200

100

010 20 30 40 50 60 70 80 90

2120579

Inte

nsity

(cps

)

(a)

1120583m

(b)

Figure 5 Filter paper and drying using a microwave

22 Characterization Field emission scanning electronmicroscopy (FE-SEM) was performed with a JEOL 6700Finstrument to observe the particle morphology and sizeSamples were gold-coated for SEM using a PS-2 coating unitThe crystal structure of the silica powder was determined byX-ray diffraction (XRD Cu target K120572 Philips DY616) and

the operation parameters were scanned in a range of 2120579 =20ndash80∘ and 40 kV The surfactant effect of the silica powderswas investigated by analyzing the surface area properties withstandard N

2gas adsorption using a surface area analyzer

The silica powders were first degassed at 250∘C for 3 hoursand the adsorptiondesorption of the liquid nitrogen was


1120583m

(a)

1120583m

(b)

Figure 6 SEM image of cubic particles

In solution Agglomeration

Heat

H2O

H2O H2O

H2O

H2O

SiO2

H2O

H2O H2O

H2O

H2O

SiO2

H2O

H2O H2O

H2O

H2O

SiO2

H2OH2O H2O H2O

H2O

H2O

H2O

H2O

SiO2

SiO2

SiO2

SiO2

SiO2 SiO2

SiO2

SiO2SiO2

SiO2

SiO2

SiO2 SiO2 SiO2

SiO2SiO2

SiO2SiO2

SiO2

SiO2

H2O

H2OH2O

H2O

Figure 7 Increasing agglomeration of particle size in reverse proportion

10 20 30 40 50 60 70 80

2120579

Inte

nsity

(cps

)

Figure 8 Effect of calcination

recorded using equilibration times at approximately 5minper point [10] The specific surface area of the nanosilicapowder was calculated by the Brunauer-Emmett-Teller(BET) method

3 Results and Discussion

The basic chemical reactions of silica powder synthesis usinga sodium silicate silica composite are

Na2SiO3+H2O + 2HCl 997888rarr Si(OH)

4+ 2NaCl

Na2SiO3+H2O +H

2SO4997888rarr Si(OH)

4+Na2SO4

Si(OCH2CH3)

4+H2O 997888rarr Si(OH)

4+ 4CH

3CH2OH

High pH range (alkaline)

Si(OH)4+OHminus 997888rarr Si(OH)

3Ominus +H

2O

Low pH range (acidic)

Si(OH)4+H3O+ 997888rarr Si(OH)

3OH+2+H2O

Polymerization

Si(OH)3Ominus+Si(OH)

3Ominus997888rarrSi(OH)

3ndashOndashSi(OH)

2Ominus+OHminus

(1)

For the synthesis of the silica powder the remaining Na+in sodium silicate was removed using sodium silica in the sol-gel process [11 12] In the silica sol the Na+ ion was breakingthe silica network structures as a modifier during silica sol-gel gelation and decreasing the purity of silica powders Toremove the sodium from sodium silicate sodium silicatewas diluted to 10wt HCl acid Silica hydrogel was madeby the sol-gel reaction after the sodium ions were removedby washing and the sodium crystallization was precipitatedby centrifugation [13 14] There are two washing methodsdeionized water washed on filter paper and a centrifugationmethod Compared to the XRD data the filter paper wasbetter for removal of Na+ ions to produce a more high-purity silica powder product however the main drawbackis the loss of silica [15ndash17] The shape of the cubic powdersilica was synthesized with 1MHCl 200mL in the water glasssolution by sol-gel The silica powder product from each of


pH 1

1120583m

1120583m

1120583m

2120583m

pH 2

200nm

pH 3

pH 4

pH 5

1120583m

pH 6

Figure 9 pH effect of particles shapes

thewashing anddryingmethodswere confirmedbyXRDandthemorphology of the particles was examined using scanningelectron microscopy (SEM) that is shown in Figures 3 4 and5

In Figure 6 the SEM images of each particle confirmthe cubic was approximately 500 nm to 1 120583m in diameterMicrowave drying could produce more aggregation than thatshown in Figure 7 increasing the particle size in reverseproportion to the specific surface area that was smaller thanthe BET data and could not be confirmed As shown in theXRD data results (Figure 8) the transition to full cristobaliteoccurred at 1200∘C The pH change of the silica compositewith reference to Figure 9 was performed Figure 9 shows thechange in the pH 1 to 6 ranges of various particle morphologyimages observed by SEM Lower pH values produced particleshapes with more spherical shapes however the BET specificsurface area data of the particles did not differ with the pHchange (Table 2)

4 Conclusions

The nanostructured silica powder particles were obtainedover a range of 500 nm to 1 120583m particle sizes with high

Table 2 Effect of pH specific surface area (m2g)

pH Specific surface area (m2g)1 857842 1403243 1370024 984145 63010

specific surface area and cubic and spherical shapes bychanging the surfactant pH and drying methods with sol-gel processThe silica powders were characterized in terms ofthe silica content specific surface area particle size particleshape and pore size distributionThe synthesis of a 10waterglass solution with 1MHCl created a mixture reaction thateffectively produced cubic particles Increasing deionizedwater and HCl molar ratios created smaller size particlesThe obtained silica nanoparticle showed high specific surfacearea


Conflict of Interests

The authors declare that they have no conflict of interests

References

[1] S Smitha P Shajesh P Mukundan T D R Nair and K G KWarrier ldquoSynthesis of biocompatible hydrophobic silica-gelatinnano-hybrid by sol-gel processrdquoColloids and Surfaces B vol 55no 1 pp 38ndash43 2007

[2] N N Ghosh and P Pramanik ldquoSynthesis of nano-sized ceramicpowders using precipitated silica in aqueous sol-gel methodrdquoNanostructured Materials vol 8 no 8 pp 1041ndash1045 1997

[3] P W J G Wijnen T P M Beelen K P J Rummens H C P LSaeijs and R A van Santen ldquoSilica gel fromwater glass a SAXSstudy of the formation and ageing of fractal aggregatesrdquo Journalof Applied Crystallography vol 24 no 5 pp 759ndash764 1991

[4] A Fouzri R Dorbez-Sridi and M Oumezzine ldquoWater con-fined in silica gel and in vycor glass at low and room temper-ature x-ray diffraction studyrdquo Journal of Chemical Physics vol116 no 2 pp 791ndash797 2002

[5] M Helmich and F Rauch ldquoOn the mechanism of diffusion ofwater in silica glassrdquo Glastechnische Berichte vol 66 no 8 pp195ndash200 1993

[6] TMatsuzawa KMase and S Inoue ldquoSynthesis and applicationof a silica nanocomposite filler using water glass and a resole-type phenol resinrdquo Journal of Applied Polymer Science vol 112no 6 pp 3748ndash3753 2009

[7] A Agarwal M Tomozawa and W A Lanford ldquoEffect ofstress on water diffusion in silica glass at various temperaturesrdquoJournal of Non-Crystalline Solids vol 167 no 1-2 pp 139ndash1481994

[8] K Aramaki ldquoSynergistic inhibition of zinc corrosion in 05M NaCl by combination of cerium(III) chloride and sodiumsilicaterdquo Corrosion Science vol 44 no 4 pp 871ndash886 2002

[9] J Yatabe T Yamada T Mogi S Yamada T Ikawa and TKageyama ldquoPreparation of porous amorphous silica fromwaterglass as raw materialsrdquoNippon Kagaku Kaishi vol 3 304 pages1993

[10] J Chandradass S Kang and D-S Bae ldquoSynthesis of silicaaerogel blanket by ambient drying method using water glassbased precursor and glass wool modified by alumina solrdquoJournal of Non-Crystalline Solids vol 354 no 34 pp 4115ndash41192008

[11] Y Arai H Segawa and K Yoshida ldquoSynthesis of nano silicaparticles for polishing prepared by sol-gel methodrdquo Journal ofSol-Gel Science and Technology vol 32 no 1ndash3 pp 79ndash83 2004

[12] A Borisov Y Lahaye and H Palme ldquoThe effect of sodium onthe solubilities of metals in silicate meltsrdquo American Mineralo-gist vol 91 no 5-6 pp 762ndash771 2006

[13] K M Davis and M Tomozawa ldquoWater diffusion into silicaglass structural changes in silica glass and their effect on watersolubility and diffusivityrdquo Journal of Non-Crystalline Solids vol185 no 3 pp 203ndash220 1995

[14] M Tomozawa D-L Kim and V Lou ldquoPreparation of highpurity low water content fused silica glassrdquo Journal of Non-Crystalline Solids vol 296 no 1-2 pp 102ndash106 2001

[15] K Kamiya A Oka H Nasu and T Hashimoto ldquoComparativestudy of structure of silica gels from different sourcesrdquo Journalof Sol-Gel Science and Technology vol 19 no 1ndash3 pp 495ndash4992000

[16] F W Chang M T Tsay M S Kuo and C M Yang ldquoCharac-terization of nickel catalysts on RHA-Al

2O3composite oxides

prepared by ion exchangerdquoApplied Catalysis A vol 226 no 1-2pp 213ndash224 2002

[17] B Andricic T Kovacic and I Klaric ldquoKinetic analysisof the thermooxidative degradation of poly(vinyl-chloride)in poly(vinyl chloride)methyl methacrylate-butadiene-styreneblendsmdash2 Nonisothermal degradationrdquo Polymer Degradationand Stability vol 79 no 2 pp 265ndash270 2003

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


Water glass

Reactor

Filter

Acid

Gel milling

New drying

Heating

Product

Washing

Water

de-Na Na

Figure 1 Flow chart showing the processing steps for the cubic silica powder

DI water Surfactant

Mixing

Washing

Aging

Water glass

Drying

Sieving

DI water

Calcination

Figure 2 Flow chart showing the processing steps for high specific surface area of nanosilica power and spherical shape particles

The high surface area silica powder manufactured for theexperimental methods was based on experimental methodsused for pH adjustment and surfactantThe reactionmixturesfor the synthesis of high surface silica powder were preparedin beakers pH 1 to 6 solutions were prepared by addingdeionized water dropwise by a pipet The other synthesis wasperformedwith different proportions of reagents surfactantsand pH which are summarized in Table 1 Sodium dodecylsulfate (SDS) was dissolved by stirring in a mixture ofdeionized water and concentrated hydrochloric acid (HCl)The stirringwas stoppedwhen themixturewas homogenizedThe mixture was aged at 50∘C in hot air drying equipmentunder static conditions for 24 hours Precipitated gelationwasfiltered off washed with 5 L deionized water and dried at

Table 1 pH reaction condition (pH 1simpH 6)

Number WG SDS Water HCI pH1 1 003 20 02 12 1 003 20 02 23 1 003 20 02 34 1 003 20 02 45 1 003 20 02 56 1 003 20 02 6

80∘C for 10 hoursThe surfactant was removed by calcinationat 700∘C for 10 hours [9]


500

400

300

200

100

010 20 30 40 50 60 70 80 90

2120579

Inte

nsity

(cps

)

(a)

1120583m

(b)


500

400

300

200

100

010 20 30 40 50 60 70 80 90

2120579

Inte

nsity

(cps

)

(a)

500nm

(b)


500

400

300

200

100

010 20 30 40 50 60 70 80 90

2120579

Inte

nsity

(cps

)

(a)

1120583m

(b)







1120583m

(a)

1120583m

(b)



Heat

H2O

H2O H2O

H2O

H2O

SiO2

H2O

H2O H2O

H2O

H2O

SiO2

H2O

H2O H2O

H2O

H2O

SiO2

H2OH2O H2O H2O

H2O

H2O

H2O

H2O

SiO2

SiO2

SiO2

SiO2

SiO2 SiO2

SiO2

SiO2SiO2

SiO2

SiO2

SiO2 SiO2 SiO2

SiO2SiO2

SiO2SiO2

SiO2

SiO2

H2O

H2OH2O

H2O


10 20 30 40 50 60 70 80

2120579

Inte

nsity

(cps

)






4+ 2NaCl

Na2SiO3+H2O +H


4+Na2SO4

Si(OCH2CH3)


4+ 4CH

3CH2OH



3Ominus +H

2O



3OH+2+H2O

Polymerization



3ndashOndashSi(OH)

2Ominus+OHminus

(1)



pH 1

1120583m

1120583m

1120583m

2120583m

pH 2

200nm

pH 3

pH 4

pH 5

1120583m

pH 6




4 Conclusions








References

















2O3composite oxides










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




500

400

300

200

100

010 20 30 40 50 60 70 80 90

2120579

Inte

nsity

(cps

)

(a)

1120583m

(b)


500

400

300

200

100

010 20 30 40 50 60 70 80 90

2120579

Inte

nsity

(cps

)

(a)

500nm

(b)


500

400

300

200

100

010 20 30 40 50 60 70 80 90

2120579

Inte

nsity

(cps

)

(a)

1120583m

(b)







1120583m

(a)

1120583m

(b)



Heat

H2O

H2O H2O

H2O

H2O

SiO2

H2O

H2O H2O

H2O

H2O

SiO2

H2O

H2O H2O

H2O

H2O

SiO2

H2OH2O H2O H2O

H2O

H2O

H2O

H2O

SiO2

SiO2

SiO2

SiO2

SiO2 SiO2

SiO2

SiO2SiO2

SiO2

SiO2

SiO2 SiO2 SiO2

SiO2SiO2

SiO2SiO2

SiO2

SiO2

H2O

H2OH2O

H2O


10 20 30 40 50 60 70 80

2120579

Inte

nsity

(cps

)






4+ 2NaCl

Na2SiO3+H2O +H


4+Na2SO4

Si(OCH2CH3)


4+ 4CH

3CH2OH



3Ominus +H

2O



3OH+2+H2O

Polymerization



3ndashOndashSi(OH)

2Ominus+OHminus

(1)



pH 1

1120583m

1120583m

1120583m

2120583m

pH 2

200nm

pH 3

pH 4

pH 5

1120583m

pH 6




4 Conclusions








References

















2O3composite oxides










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




1120583m

(a)

1120583m

(b)



Heat

H2O

H2O H2O

H2O

H2O

SiO2

H2O

H2O H2O

H2O

H2O

SiO2

H2O

H2O H2O

H2O

H2O

SiO2

H2OH2O H2O H2O

H2O

H2O

H2O

H2O

SiO2

SiO2

SiO2

SiO2

SiO2 SiO2

SiO2

SiO2SiO2

SiO2

SiO2

SiO2 SiO2 SiO2

SiO2SiO2

SiO2SiO2

SiO2

SiO2

H2O

H2OH2O

H2O


10 20 30 40 50 60 70 80

2120579

Inte

nsity

(cps

)






4+ 2NaCl

Na2SiO3+H2O +H


4+Na2SO4

Si(OCH2CH3)


4+ 4CH

3CH2OH



3Ominus +H

2O



3OH+2+H2O

Polymerization



3ndashOndashSi(OH)

2Ominus+OHminus

(1)



pH 1

1120583m

1120583m

1120583m

2120583m

pH 2

200nm

pH 3

pH 4

pH 5

1120583m

pH 6




4 Conclusions








References

















2O3composite oxides










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




pH 1

1120583m

1120583m

1120583m

2120583m

pH 2

200nm

pH 3

pH 4

pH 5

1120583m

pH 6




4 Conclusions








References

















2O3composite oxides










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






References

















2O3composite oxides










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



research article synthesis of high surface area mesoporous ...research article synthesis of high...

Documents