Emergence of nanoscience in scores of industrial and scientific developments has generated a concern for environmental impact as an immeasurable quantity of nanoparticles is released into natural resources. Two potential effects on drinking water treatment are:

1. NP may adsorb VOC bypass treatment by PAC completely

2. NOM may compete with VOC for adsorption by PAC VOC won’t settle out (by blocking adsorption sites, filling sites, and

changing the electrical charges on NP)

This study will investigate these effects on water treatment.

Experimental Experimental StrategiesStrategies

RefereReferencesnces

ConclusConclusionsions

ResResultsults

IntroduIntroductionction

Nanoparticles: Good Technology = Bad Water?Nanoparticles: Good Technology = Bad Water?Effects of Iron Oxide Nanoparticles on Adsorption of TCE by PAC

Kurt Whitford1, Melissa Stolz2, Hafiz Salih3, Dr. George Sorial4

1Glen Este High School, Cincinnati, OH; 2RA Jones Middle School, Florence, KY; 3,4University of Cincinnati, Department of Civil and Environmental Engineering, Cincinnati, OH

AcknowledgementsThe authors wish to acknowledge the contributions of Dr. Anant Kukreti and Andrea Burrows, UC RET Program Coordinators.

Nanoparticles (NP) may adversely affect the adsorption of volatile organic compounds (VOC’s), onto activated carbon, the current best available technology for water treatment. This research focuses on the potentially inhibiting effects of humic acid (HA), NOM, and nanoparticle iron oxide on the adsorption of trichloroethylene (TCE) by powdered activated carbon (PAC). Six isotherms were prepared using various combinations of TCE, PAC, HA, and Fe2O3. The study established a relationship between the amount of TCE adsorbed and amount of PAC used. It was also found that NP ‘s act as a secondary adsorbent for TCE, though both PAC and NP adsorption of TCE is inhibited in the presence of humic acid.

Project GoalsProject GoalsThis project seeks to investigate the impact of iron oxide nanoparticles on adsorption of trichloroethylene (TCE) by powdered activated carbon (PAC) in the presence and absence of NOM (Humic Acid). Secondary objectives are to calculate Freundlich isotherm constants for all TCE, PAC, NP and HA combinations and generate data on the kinetics of TCE adsorption onto PAC.

Isotherm samples were prepared using deionized water at pH 7 in amber bottles treated with varying amounts of PAC mixed for 14 days filtered using 0.45 micrometer paper analyzed for TCE adsorption using GC-FID

Adsorption of humic acid onto nanoscale zerovalent iron and its effect on arsenic removal.Giasuddin,A.B.; Kanel,S.R.; Choi,H.Environ.Sci.Technol., 2007, 41, 6, 2022-2027, United StatesTCE removal from contaminated soil and ground waterRussell, H.H.; Matthews, J. E.; Sewell, G.W.US EPA, Office of Research and Development, EPA/540/S-92/002, Jan 1992, United StatesNanomaterials in the environment: behavior, fate, bioavailability, and effectsKlaine, S.J, et al.Environ. Toxicol. Chem., 2008, 27,9, 1825-1851, United StatesScience and technology of nanomaterials: current status and future prospectsRao, C.N.R.; Cheetham, A.K.J. Mater Chem, 2001, 11, 2887-2894, United Kingdom

1. Adsorption of TCE onto iron oxide nanoparticles provides a mechanism for bypassing activated carbon treatment of water.

2. Humic acid serves to further inhibit TCE adsorption in the presence of nanoparticles.

3. Future research should focus on optimizing PAC performance in the presence of NOM and nanoparticles.

1. Fe2O3 increased the removal

of TCE beyond that which was removed by PAC alone.

2. Humic acid lowered the adsorption of TCE by PAC, diminishing the increases observed when nanoparticles are present.

Parameter

pHpzc

(0.001MKH2PO4)

pHpzc

(0.001M KH2PO4

+5mg/l Humic Acid)

Charge (millivolts)

(0.001MKH2PO4)

Charge

(0.001M KH2PO4 +5mg/l

Humic Acid)

SiO2 1.9 <1.8pH 7

(-37.9)

pH 7

(-35.0)

TiO2 2.4 < 1.8pH 7

(-39.4)

pH 7

(-45.3)

Fe2O3 7.7 < 1.8pH 7

(+17.8)

pH 3.5

(-28.0)

PAC 3.2 2.5pH 7

(+28.8)

pH 7

(-41.3)

Adsorption of TCE in the Presence and Absence of Fe2O3 And HA

Log Ce

1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2

Lo

g q e

1.0

1.2

1.4

1.6

1.8

2.01.0mg/l Fe2O3 + 10mg/l HA

0.5 mg/l Fe2O3 + 10mg/l HA

NO HA+ No Fe2O3HA +No Fe2O30.5 mg/l Fe2O3 + No HA 1.0 Fe2O3 + No HA