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).

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