Transcript Slide 1

Nanoparticles: Good Technology = Bad Water?
Effects of Iron Oxide Nanoparticles on Adsorption of TCE by PAC
Kurt
1Glen
1
Whitford ,
Melissa
2
Stolz ,
Hafiz
3
Salih ,
Dr. George
4
Sorial
Este High School, Cincinnati, OH; 2RA Jones Middle School, Florence, KY; 3,4University of Cincinnati, Department of Civil and Environmental Engineering, Cincinnati, OH
Project Goals
This 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.
Results
1. Fe2O3 increased the removal
of TCE beyond that which
was removed by PAC alone.
Introduction
SiO2
1.9
TiO2
<1.8
2.4
Fe2O3
< 1.8
7.7
PAC
< 1.8
3.2
2.5
pH 7
pH 7
(-37.9)
(-35.0)
pH 7
pH 7
(-39.4)
(-45.3)
pH 7
pH 3.5
(+17.8)
(-28.0)
pH 7
pH 7
(+28.8)
(-41.3)
A d s o rp tio n o f T C E in th e P re s e n c e a n d A b s e n c e
o f F e 2O 3 A n d H A
Amount of TCE Removed
40
2 .0
1 .0 m g /l F e O + 1 0 m g /l H A
2 3
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:
bypass treatment by PAC completely
2. NOM may compete with VOC for adsorption by PAC
(by blocking adsorption sites, filling sites, and
changing the electrical charges on NP)
This study will investigate these effects on water treatment.
VOC won’t settle out
Mean ug TCE/g PAC
35
Emergence of nanoscience in scores of industrial and scientific developments has
1. NP may adsorb VOC
Charge
(millivolts)
pHpzc
Paramete
(0.001M KH2PO4
(0.001M
r
(0.001MKH2PO4) +5mg/l Humic
KH2PO4 +5mg/l
(0.001MKH2PO4)
Acid)
Humic Acid)
2. Humic acid lowered the
adsorption of TCE by PAC,
diminishing the increases
observed when
nanoparticles are present.
45
Charge
Baseline 1: PAC + TCE
NO HA+ No Fe O
2 3
1 .8
30
HA +No Fe O
2 3
Baseline 2: PAC + TCE +HA
0 .5 m g /l F e 2 O 3 + N o H A
1 .0 F e 2 O 3 + N o H A
25
Set 1: PAC + TCE + 0.5 mg/L NP
20
Set 2: PAC + TCE + 1.0 mg/L NP
15
10
Set 3: PAC + TCE + 0.5 mg/L
Fe2O3 + HA
5
Set 4: PAC + TCE + 1.0 mg/L
Fe2O3 + HA
1 .6
1 .4
1 .2
1 .0
0
1 .6
1 .8
2 .0
Isotherm Condition
Conclusions
2 .2
2 .4
2 .6
2 .8
3 .0
3 .2
Log Ce
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.
Experimental Strategies
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
0 .5 m g /l F e O + 1 0 m g /l H A
2 3
Log q e
Abstract
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.
pHpzc
3. Future research should focus on optimizing PAC performance in the
presence of NOM and nanoparticles.
References
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 States
TCE removal from contaminated soil and ground water
Russell, H.H.; Matthews, J. E.; Sewell, G.W.
US EPA, Office of Research and Development, EPA/540/S-92/002, Jan 1992, United States
Nanomaterials in the environment: behavior, fate, bioavailability, and effects
Klaine, S.J, et al.
Environ. Toxicol. Chem., 2008, 27,9, 1825-1851, United States
Science and technology of nanomaterials: current status and future prospects
Rao, C.N.R.; Cheetham, A.K.
J. Mater Chem, 2001, 11, 2887-2894, United Kingdom
Acknowledgements
The authors wish to acknowledge
the contributions of Dr. Anant
Kukreti and Andrea Burrows, UC
RET Program Coordinators.