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Li Z, Samonte PRV, Cao H, Miesel JR, Xu W. Assess the formation of disinfection by-products from pyrogenic dissolved organic matter (pyDOM): impact of wildfire on the water quality of forest watershed. Sci Total Environ 2023; 898:165496. [PMID: 37451447 DOI: 10.1016/j.scitotenv.2023.165496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/06/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Wildfires can release pyrogenic dissolved organic matter (pyDOM) into the forest watershed, which may pose challenges for water treatment operations downstream due to the formation of disinfection by-products (DBPs). In this study, we systematically assessed the physio-chemical properties of pyDOM (e.g., electron-donating and -accepting capacities; EDC and EAC) and their contributions to DBP formation under different disinfection scenarios using (1) ten lab samples produced from various feedstocks and pyrolysis temperatures, and (2) pre- and post-fire field samples with different burning severities. A comprehensive suite of DBPs-four trihalomethanes (THMs), nine haloacetic acids (HAAs), and seven N-nitrosamines-were included. The formations of THM and HAA showed an up to 5.7- and 8.9-fold decrease as the pyrolysis temperature increased, while the formation of N-nitrosamines exhibited an up to 6.6-fold increase for the laboratory-derived pyDOM. These results were supported by field pyDOM samples, where the post-fire samples consistently showed a higher level of N-nitrosamine formation (i.e., up to 5.3-fold), but lower THMs and HAAs compared to the pre-fire samples. To mimic environmental reducing conditions, two field samples were further reduced electrochemically and compared with Suwannee River natural organic matter (SRNOM) to evaluate their DBP formation. We found increased DBP formation in pyDOM samples following electrochemical reduction but not for SRNOM, which showed increased N-nitrosamines but decreased THMs and HAAs post-electrochemical reduction. Furthermore, this study reported for the first time the formation of two previously overlooked N-nitrosamines (i.e., nitrosodiethylamine (NDEA), N-nitrosodi-n-propylamine (NDPA)) in both laboratory and field pyDOM samples, raising concerns for drinking water safety given their higher toxicity as compared to the regulated counterparts. Results from this study provide new insights for DBP mitigation during post-fire recovery, which are particularly relevant to communities that rely on forest watersheds as their drinking water sources.
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Affiliation(s)
- Zhao Li
- Department of Civil and Environmental Engineering, Villanova University, 800 E. Lancaster Ave., Villanova, PA 19085, United States of America
| | - Pamela Rose V Samonte
- Department of Civil and Environmental Engineering, Villanova University, 800 E. Lancaster Ave., Villanova, PA 19085, United States of America
| | - Han Cao
- Department of Civil and Environmental Engineering, Villanova University, 800 E. Lancaster Ave., Villanova, PA 19085, United States of America
| | - Jessica R Miesel
- Department of Plant, Soil and Microbial Sciences, Michigan State University, 220 Trowbridge Rd, East Lansing, MI 48824, United States of America
| | - Wenqing Xu
- Department of Civil and Environmental Engineering, Villanova University, 800 E. Lancaster Ave., Villanova, PA 19085, United States of America.
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Li Z, Jorn R, Samonte PRV, Mao J, Sivey JD, Pignatello JJ, Xu W. Surface-catalyzed hydrolysis by pyrogenic carbonaceous matter and model polymers: An experimental and computational study on functional group and pore characteristics. Appl Catal B 2022; 319:121877. [PMID: 37846345 PMCID: PMC10578355 DOI: 10.1016/j.apcatb.2022.121877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
We employed a polymer network to understand what properties of pyrogenic carbonaceous matter (PCM; e.g., activated carbon) confer its reactivity, which we hereinafter referred to as PCM-like polymers (PLP). This approach allows us to delineate the role of functional groups and micropore characteristics using 2,4,6-trinitrotoluene (TNT) as a model contaminant. Six PLP were synthesized via cross-coupling chemistry with specific functionality (-OH, -NH2, -N(CH3)2, or -N ( CH 3 ) 3 + ) and pore characteristics (mesopore, micropore). Results suggest that PCM functionality catalyzed the reaction by: (1) serving as a weak base (-OH, -NH2) to attack TNT, or (2) accumulating OH- near PCM surfaces (-N ( CH 3 ) 3 + ). Additionally, TNT hydrolysis rates, pH and co-ion effects, and products were monitored. Microporous PLP accelerated TNT decay compared to its mesoporous counterpart, as further supported by molecular dynamics modeling results. We also demonstrated that quaternary ammonium-modified activated carbon enhanced TNT hydrolysis. These findings have broad implications for pollutant abatement and catalyst design.
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Affiliation(s)
- Zhao Li
- Department of Civil and Environmental Engineering, Villanova University, Villanova, PA 19085, USA
| | - Ryan Jorn
- Department of Chemistry, Villanova University, Villanova, PA 19085, USA
| | - Pamela Rose V. Samonte
- Department of Civil and Environmental Engineering, Villanova University, Villanova, PA 19085, USA
| | - Jingdong Mao
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529, USA
| | - John D. Sivey
- Department of Chemistry, Towson University, Towson, MD 21252, USA
| | - Joseph J. Pignatello
- Department of Environmental Sciences, The Connecticut Agricultural Experiment Station, 123 Huntington St., New Haven, CT 06511, USA
| | - Wenqing Xu
- Department of Civil and Environmental Engineering, Villanova University, Villanova, PA 19085, USA
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Samonte PRV, Li Z, Mao J, Chaplin BP, Xu W. Pyrogenic carbon-promoted haloacetic acid decarboxylation to trihalomethanes in drinking water. Water Res 2022; 210:117988. [PMID: 34959066 PMCID: PMC9195562 DOI: 10.1016/j.watres.2021.117988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Drinking water disinfection by chlorination or chloramination can result in the formation of disinfection byproducts (DBPs) such as haloacetic acids (HAAs) and trihalomethanes (THMs). Pyrogenic carbonaceous matter (PCM), such as activated carbon (AC), is commonly used as an ostensibly inert adsorbent to remove HAAs from water. HAA degradation has been mainly attributed to biological factors. This study, for the first time, revealed that abiotic HAA degradation in the presence of PCM could be important under water treatment conditions. Specifically, we observed complete destruction of Br3AA, a model HAA, in the presence of powder AC at pH 7 within 30 min. To understand the role of PCM and the reaction mechanism, we performed a systematic study using a suite of HAAs and various PCM types. We found that PCM significantly accelerated the transformation of three HAAs (Br3AA, BrCl2AA, Br2ClAA) at pH 7. Product characterization indicated an approximately 1:1 HAA molar transformation into their respective THMs following a decarboxylation pathway with PCM. The Br3AA activation energy (Ea) was measured by kinetic experiments at 15-45 °C with and without a model PCM, wherein a significant decrease in Ea from 25.7 ± 3.2 to 13.6 ± 2.2 kcal•mol-1 was observed. We further demonstrated that oxygenated functional groups on PCM (e.g., -COOH) can accelerate HAA decarboxylation using synthesized polymers to resemble PCM. Density functional theory simulations were performed to determine the enthalpy of activation (ΔH‡) for Br3AA decarboxylation with H3O+ and formic acid (HCOOH). The presence of HCOOH significantly lowered the overall ΔH‡ value for Br3AA decarboxylation, supporting the hypothesis that -COOH catalyzes the C-C bond breaking in Br3AA. Overall, our study demonstrated the importance of a previously overlooked abiotic reaction pathway, where HAAs can be quickly converted to THMs with PCM under water treatment relevant conditions. These findings have substantial implications for DBP mitigation in water quality control, particularly for potable water reuse or pre-chlorinated water that allow direct contact between HAAs and AC during filtration as well as PAC fines traveling with finished water in water distribution systems. As such, the volatilization and relative low toxicity of volatile THMs may be considered as a detoxification process to mitigate adverse DBP effects in drinking water, thereby lowering potential health risks to consumers.
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Affiliation(s)
- Pamela Rose V Samonte
- Department of Civil and Environmental Engineering, Villanova University, 800 E. Lancaster Ave., Villanova, PA 19085, United States
| | - Zhao Li
- Department of Civil and Environmental Engineering, Villanova University, 800 E. Lancaster Ave., Villanova, PA 19085, United States
| | - Jingdong Mao
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529, United States
| | - Brian P Chaplin
- Department of Chemical Engineering, University of Illinois at Chicago, 929 W. Taylor St., Chicago, IL 60607, United States; Institute of Environmental Science and Policy, University of Illinois at Chicago, 1603 W. Taylor St., Chicago, IL 60612, United States; Department of Civil, Materials, and Environmental Engineering, University of Illinois at Chicago, 842 W. Taylor St., Chicago, IL 60607, United States
| | - Wenqing Xu
- Department of Civil and Environmental Engineering, Villanova University, 800 E. Lancaster Ave., Villanova, PA 19085, United States.
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Almassi S, Samonte PRV, Li Z, Xu W, Chaplin BP. Mechanistic Investigation of Haloacetic Acid Reduction Using Carbon-Ti 4O 7 Composite Reactive Electrochemical Membranes. Environ Sci Technol 2020; 54:1982-1991. [PMID: 31876410 DOI: 10.1021/acs.est.9b06744] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Carbon-Ti4O7 composite reactive electrochemical membranes (REMs) were studied for adsorption and electrochemical reduction of haloacetic acids (HAAs). Powder activated carbon (PAC) or multiwalled carbon nanotubes (MWCNTs) were used in these composites. Results from flow-through adsorption experiments with dibromoacetic acid (DBAA) as a model HAA were interpreted with a transport model. It was estimated that ∼46% of C in the MWCNT-REM and ∼10% of C in the PAC-REM participated in adsorption reactions. Electrochemical reduction of 1 mg L-1 DBAA in 10 mM KH2PO4/K2HPO4 at -1.5 V/SHE (hydraulic residence time, ∼11 s) resulted in 73, 94, and 96% DBAA reduction for Ti4O7, PAC-Ti4O7, and MWCNT-Ti4O7 REMs, respectively. The reactive-transport model yielded kobs values between 9.16 and 33.3 min-1, which were 2 to 4 orders of magnitude higher than previously reported. PAC-Ti4O7 REM was tested with tap water spiked with 0.11 mg L-1 of nine different HAAs in a similar reduction experiment. The results indicated that all HAAs were reduced to <20 μg L-1. Moreover, the total combined concentration of five regulated HAAs was lower than the regulatory limit (60 μg L-1). Density functional theory simulations suggest that a direct electron transfer reaction was the probable rate-determining step for HAA reduction.
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Affiliation(s)
- Soroush Almassi
- Department of Chemical Engineering , University of Illinois at Chicago , 945 West Taylor Street , Chicago , Illinois 60607 , United States
| | - Pamela Rose V Samonte
- Department of Chemical Engineering , Villanova University , 800 East Lancaster Avenue , Villanova , Pennsylvania 19085 , United States
| | - Zhao Li
- Department of Civil and Environmental Engineering , Villanova University , 800 East Lancaster Avenue , Villanova , Pennsylvania 19085 , United States
| | - Wenqing Xu
- Department of Civil and Environmental Engineering , Villanova University , 800 East Lancaster Avenue , Villanova , Pennsylvania 19085 , United States
| | - Brian P Chaplin
- Department of Chemical Engineering , University of Illinois at Chicago , 945 West Taylor Street , Chicago , Illinois 60607 , United States
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Rocard JM, Asadishad B, Samonte PRV, Ghoshal S, Tufenkji N. Natural freeze-thaw cycles may increase the risk associated with Salmonella contamination in surface and groundwater environments. Water Res X 2018; 1:100005. [PMID: 31194033 PMCID: PMC6549903 DOI: 10.1016/j.wroa.2018.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Groundwater contamination by bacteria poses a serious threat to our drinking water supplies. In cold climate regions, microorganisms introduced to upper soil layers by spreading of animal manure are subject to low temperatures and multiple cycles of freezing and thawing at the beginning of winter and during spring melt. We investigated the influence of temperature fluctuations around the freezing point, known as freeze-thaw (FT), on the inactivation rates, growth, and biofilm formation of a manure-isolated strain of Salmonella typhimurium. Moreover, the effects of FT on the transport characteristics of S. typhimurium in quartz sand were monitored in model porewater solutions of two different ionic strengths (IS: 10 and 100 mM KCl) and two different humic acid (HA) concentrations (1 and 5 mg/L). Increasing numbers of FT cycles were found to decrease the deposition of S. typhimurium onto quartz sand and increase the percentage of detached cells in sand-packed column experiments. Based on the calculated bacterial attachment efficiencies, the predicted minimum setback distances between the location of water supply wells and manure spreading activities are higher when the effects of FT are taken into consideration. While FT treatment significantly affected cell viability (in the presence of HA), most cells were in a viable but non-culturable (VBNC) state with compromised ability to form biofilm. This investigation demonstrates the effects of spring temperature variations in upper soil layers on S. typhimurium properties and the potential increased risk of bacterial contamination in representative aquifer environments in cold climate regions.
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Affiliation(s)
- Jennifer M. Rocard
- Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5, Canada
- Department of Civil Engineering, McGill University, Montreal, Quebec, H3A 0C3, Canada
| | - Bahareh Asadishad
- Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5, Canada
| | - Pamela Rose V. Samonte
- Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5, Canada
| | - Subhasis Ghoshal
- Department of Civil Engineering, McGill University, Montreal, Quebec, H3A 0C3, Canada
| | - Nathalie Tufenkji
- Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5, Canada
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