1. Shah A.D., Liu,
Zhengqian, Salhi E., Höfer, T., and von Gunten U. (2015)
“Formation of disinfection by-products during ballast water
treatment with ozone, chlorine, and peracetic acid: influence
of water quality parameters”, Environmental Science: Water
Research & Technology, DOI: 10.1039/C5EW00061K.
2. Shah A.D., Liu, Zhengqian, Salhi
E., Höfer, T., and von Gunten U. (2015) “Peracetic acid
oxidation of saline waters in absence and presence of H2O2:
secondary oxidant and disinfection by-product formation”, Environmental
Science and Technology, 49, 1698-1705.
3. Werschkun, B., Banerji, S., Oihane C.,
Basurko Matej, D., Fuhr, F., Gollasch, S., Grummt, T.,
Haarich, M., Jha, A.N., Kacan, S., Kehrer, A., Linders, J.,
Mesbahi, E., Pughiuc, D., Richardson, S.D., Schwarz-Schulz,
B., Shah, A.D., Theobald, N., von Gunten, U., Wieck,
S., Höfer, T. (2014) “Emerging risks from ballast water
treatment: The run-up to the International Ballast Water
Management Convention”, Chemophere, 112, 256-266.
4. Shah, A.D.; Dai, N.; Mitch, W.A.
(2013) “Application of Ultraviolet, Ozone, and Advanced
Oxidation Treatments to Washwaters to Destroy Nitrosamines,
Nitramines, Amines, and Aldehydes formed during Amine-based
Carbon Capture”, Environmental Science and Technology,
47, 2799-2808.
5. Dai, N.; Shah, A.D.; Hu, L.;
Plewa, M.J.; McKague, B.; Mitch, W.A. (2012) “Measurement of
nitrosamine and nitramine formation from NOx reactions with
amines during amine-based carbon dioxide capture for
postcombustion carbon sequestration”, Environmental
Science and Technology, 46, 9793-9801.
6. Shah, A.D.; Krasner, S.; Lee,
C.F.T.; von Gunten, U.; Mitch, W.A. (2012) “Trade-offs in
Disinfection Byproduct Formation Associated with Precursor
Preoxidation for Control of N-Nitrosodimethylamine Formation”,
Environmental Science and Technology, 46, 4809-4818.
7. Shah, A.D.; Mitch, W.A. (2012)
“Halonitroalkane, halonitriles, haloamides, and
N-nitrosamines: a critical review of N-nitrogenous
disinfection byproduct (N-DBP) formation pathways”, Environmental
Science and Technology, 46, 119-131.
8. Shah, A. D.; Huang, C.-H.; Kim,
J.-H. (2012) “Mechanisms of Antibiotic Removal by
Nanofiltration Membranes: Model Development and
Application”, Journal
of Membrane Science, 389, 234-244.
9. Shah, A. D.; Kim, J.-H.; Huang,
C.-H. (2011) “Tertiary Amines Enhance Reactions of Organic
Contaminants with Aqueous Chlorine”, Water Research,
45, 6087-6096.
10. Shah,
A.D.; Dotson, A.D.; Linden, K.G.; Mitch, W.A. (2011)
“Impact of UV Disinfection Combined with
Chlorination/Chloramination on the Formation of
Halonitromethanes and Haloacetonitriles in Drinking Water”,
Environmental Science and Technology, 45, 3657-3664.
11. Shah,
A. D.; Kim, J. -H.; Huang, C. -H. (2006) “Reaction
Kinetics and Transformation of Carbadox and Structurally
Related Compounds with Aqueous Chlorine”, Environmental
Science and Technology, 40, 7228-7235.
12.
Dodd, M. C., Shah, A. D., von Gunten, U. and Huang,
C.-H. (2005) “Interactions of Fluoroquinolone Antibacterial
Agents with Aqueous Chlorine: Kinetics, Reaction Mechanisms,
and Transformation Pathways”, Environmental Science and
Technology, 39, 7065-7076.
ONGOING PROJECTS:
Investigating
the Photochemical Pathways of Organic Sulfur in forming COS
and CS2 in Natural Waters: Implications to the
Global Radiation Budget
This project evaluates the key reaction
pathways involved during sunlight photolysis of dissolved
organic sulfur in natural waters towards forming the volatile
sulfur compounds, COS and CS2. Evaluating
such photochemical pathways are important because COS and CS2
can be released from water into the atmosphere where they can
be oxidized in the stratosphere to form sulfate aerosols,
which are known to counteract global warming by reflecting
solar radiation. One potential issue is the uncertainty
of COS released from natural waters. While previous
studies have linked COS and CS2 formation in
surface seawaters to the indirect photolysis of organic sulfur
compounds such as cysteine, a clear understanding of the
precursors, reactive intermediates, and photolytic
transformation pathways involved is still needed. This
is especially true given that COS and CS2
formation is likely driven by sunlight-generated photooxidants
and reactive oxygen species derived from various water quality
constituents (e.g. dissolved organic matter (DOM), O2,
chloride and bromide). Thus, the overall objective of
this project is to isolate how such differences in water type
that include real freshwaters, coastal brackish waters, and
seawaters affect COS and CS2 formation during
sunlight photolysis so that a better predictive model can be
derived for the global COS/sulfur budget
estimates.
Membrane Pre-treatment using
Chemical Disinfectants in Halide Impaired Waters
(collaboration with
John Howarter, MSE, Purdue University)
This project is focused on evaluating the chemistry of
organic nitrogen compounds that make-up nanofiltration and
reverse osmosis membrane surface functional groups.
Since disinfectants such as chlorine and chloramines can be
used prior to filtration to reduce biofouling, research is
currently being conducted on how these disinfectants react
with the membrane surface and what the resulting effects are
on membrane performance. This would be especially
important in brackish and seawaters which are used in
desalination and water reuse and contain high levels of
bromide and chloride that could result in secondary oxidant
formation (e.g. HOBr, Br2, Cl2,
etc.). The specific objectives of this work are to
investigate the chlorination potential of various model
compounds and polymer fragments (up to 5000 amu) by LC/MS/MS
analysis in the presence of varying halide
concentrations. In addition, additionlal experients
will use a bench-scale cross flow membrane filtration system
where membrane performance following pre-treatment in halide
impaired waters will be evaluated.
Tradeoffs in disinfection by-product
formation: the role of tertiary amines during chloramination
of wastewater and drinking water
This project aims to
elucidate the tradeoffs in disinfection by-product formation
when tertiary amines play a dual role in which they can
either i) serve as precursors to strong oxidant
formation by forming the chlorammonium ion (Cl-N+R1R2)
and enhance haloform (CHX3) formation following
reaction with organic contaminants or ii) undergo elimination
to form secondary amines which are further oxidized to
nitrosamines.
Influence of Halides
on forming Nitrogen-based Disinfection By-Products
This
project is intended to investigate the potential for
chloride and bromide to increase nitrogen-based disinfection
byproduct formation (N-DBPs) during chlorination through
formation of secondary oxidants (e.g. Cl2, Br2,
etc).
Disinfection
By-product Formation from Household Plastic Pipes
(collaboration with Andrew Whelton, CE/EEE, Purdue University)
This project is
intended to investigate the potential for plastic pipes
commonly used in US homes to leach contaminants in the
drinking water that may react with chemical disinfectants to
form various disinfection byproducts, including
trihalomethanes (THMs).