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Sviatenko LK, Gorb L, Leszczynski J. 5-Amino-1,2,4-triazol-3-one Degradation by Indirect Photolysis: A Density Functional Theory Study. J Phys Chem A 2024; 128:6825-6833. [PMID: 39074302 DOI: 10.1021/acs.jpca.4c02298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
Sunlight irradiation induces formation of reactive oxygen species (superoxide, hydroperoxyl radical, singlet oxygen, etc.), which readily take part in degradation of environmental pollutants. Being a primary ingredient in a suite of insensitive munition formulations, NTO (5-nitro-1,2,4-triazol-3-one) can be released onto training range soils and reduced to ATO (5-amino-1,2,4-triazol-3-one) by soil bacteria or iron-contained minerals. ATO can be dissolved in surface water and groundwater due to its good water solubility and then undergo further decomposition. A detailed investigation of possible mechanisms for ATO decomposition in water induced by superoxide, hydroperoxyl radical, and singlet oxygen as pathways for ATO environmental degradation was performed by computational study at the PCM(Pauling)/M06-2X/6-311++G(d,p) level. Hydrolysis and degradation of ATO induced by superoxide are unlikely to occur due to the high activation energy or endergonicity of the processes. The hydroperoxyl radical causes rapid and reversible hydrogen transfer from ATO, while an attachment of the hydroperoxyl radical to ATO can induce decomposition of ATO, leading to its mineralization. Singlet oxygen shows a higher reactivity toward ATO than the hydroperoxyl radical. Decomposition of ATO was found to be a multistep process that begins with singlet oxygen attachment to the carbon atom of the C═N double bond. The intermediate that is formed undergoes recyclization, cycle opening, and sequential elimination of nitrogen gas, ammonia, and carbon(IV) oxide. Isocyanic acid, which arises intermediately, hydrolyzes into ammonia and carbon(IV) oxide. Calculated activation energies and high exergonicity of the studied processes support the contribution of singlet oxygen and the hydroperoxyl radical to ATO degradation into low-weight inorganic compounds in the environment.
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Affiliation(s)
- Liudmyla K Sviatenko
- Department of Chemistry, Physics & Atmospheric Sciences, Jackson State University, Jackson, Mississippi 39217, United States
| | - Leonid Gorb
- Institute of Molecular Biology and Genetics, NAS of Ukraine, 150 Zabolotny Str., Kyiv 03143, Ukraine
- QSAR Lab Sp. z o.o. Trzy Lipy 3, B, Gdansk 80-172, Poland
| | - Jerzy Leszczynski
- Department of Chemistry, Physics & Atmospheric Sciences, Jackson State University, Jackson, Mississippi 39217, United States
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Ou C, Yuan S, Manabu F, Shi K, Elsamadony M, Zhang J, Qin J, Shi J, Liao Z. Insight into the mechanism of chlorinated nitroaromatic compounds anaerobic reduction with mackinawite (FeS) nanoparticles. JOURNAL OF HAZARDOUS MATERIALS 2024; 471:134451. [PMID: 38691935 DOI: 10.1016/j.jhazmat.2024.134451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 04/12/2024] [Accepted: 04/25/2024] [Indexed: 05/03/2024]
Abstract
Anaerobic biotechnology for wastewaters treatment can nowadays be considered as state of the art methods. Nonetheless, this technology exhibits certain inherent limitations when employed for industrial wastewater treatment, encompassing elevated substrate consumption, diminished electron transfer efficiency, and compromised system stability. To address the above issues, increasing interest is being given to the potential of using conductive non-biological materials, e,g., iron sulfide (FeS), as a readily accessible electron donor and electron shuttle in the biological decontamination process. In this study, Mackinawite nanoparticles (FeS NPs) were studied for their ability to serve as electron donors for p-chloronitrobenzene (p-CNB) anaerobic reduction within a coupled system. This coupled system achieved an impressive p-CNB removal efficiency of 78.3 ± 2.9% at a FeS NPs dosage of 1 mg/L, surpassing the efficiencies of 62.1 ± 1.5% of abiotic and 30.6 ± 1.6% of biotic control systems, respectively. Notably, the coupled system exhibited exclusive formation of aniline (AN), indicating the partial dechlorination of p-CNB. The improvements observed in the coupled system were attributed to the increased activity in the electron transport system (ETS), which enhanced the sludge conductivity and nitroaromatic reductases activity. The analysis of equivalent electron donors confirmed that the S2- ions dominated the anaerobic reduction of p-CNB in the coupled system. However, the anaerobic reduction of p-CNB would be adversely inhibited when the FeS NPs dosage exceeded 5 g/L. In a continuous operation, the p-CNB concentration and HRT were optimized as 125 mg/L and 40 h, respectively, resulting in an outstanding p-CNB removal efficiency exceeding 94.0% after 160 days. During the anaerobic reduction process, as contributed by the predominant bacterium of Thiobacillus with a 6.6% relative abundance, a mass of p-chloroaniline (p-CAN) and AN were generated. Additionally, Desulfomonile was emerged with abundances ranging from 0.3 to 0.7%, which was also beneficial for the reduction of p-CNB to AN. The long-term stable performance of the coupled system highlighted that anaerobic technology mediated by FeS NPs has a promising potential for the treatment of wastewater containing chlorinated nitroaromatic compounds, especially without the aid of organic co-substrates.
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Affiliation(s)
- Changjin Ou
- Nantong Key Laboratory of Intelligent and New Energy Materials, School of Chemistry and Chemical Engineering, Nantong University, Nantong 222100, China
| | - Sujuan Yuan
- Nantong Key Laboratory of Intelligent and New Energy Materials, School of Chemistry and Chemical Engineering, Nantong University, Nantong 222100, China
| | - Fujii Manabu
- Civil and Environmental Engineering Department, School of Environment and Society, Tokyo Institute of Technology, Meguro-Ku, Tokyo 152-8552, Japan
| | - Ke Shi
- Nantong Key Laboratory of Intelligent and New Energy Materials, School of Chemistry and Chemical Engineering, Nantong University, Nantong 222100, China
| | - Mohamed Elsamadony
- Department of Mechanical Engineering, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia; Interdisciplinary Research Center for Refining & Advanced Chemicals, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia
| | - Juntong Zhang
- Nantong Key Laboratory of Intelligent and New Energy Materials, School of Chemistry and Chemical Engineering, Nantong University, Nantong 222100, China
| | - Juan Qin
- Nantong Key Laboratory of Intelligent and New Energy Materials, School of Chemistry and Chemical Engineering, Nantong University, Nantong 222100, China
| | - Jian Shi
- Nantong Key Laboratory of Intelligent and New Energy Materials, School of Chemistry and Chemical Engineering, Nantong University, Nantong 222100, China.
| | - Zhipeng Liao
- Nantong Key Laboratory of Intelligent and New Energy Materials, School of Chemistry and Chemical Engineering, Nantong University, Nantong 222100, China.
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Yu Y, Root RA, Sierra-Alvarez R, Chorover J, Field JA. Treatment of the insensitive munitions compound, 3-nitro-1,2,4-triazol-5-one (NTO), in flow-through columns packed with zero-valent iron. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:64606-64616. [PMID: 37071366 DOI: 10.1007/s11356-023-26922-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 04/06/2023] [Indexed: 05/11/2023]
Abstract
The need for effective technologies to remediate the insensitive munitions compound 3-nitro-1,2,4-triazol-5-one (NTO) is emerging due to the increasing use by the US Army and environmental concerns about the toxicity and aqueous mobility of NTO. Reductive treatment is essential for the complete degradation of NTO to environmentally safe products. The objective of this study is to investigate the feasibility of applying zero-valent iron (ZVI) in a continuous-flow packed bed reactor as an effective NTO remediation technology. The ZVI-packed columns treated an acidic influent (pH 3.0) or a circumneutral influent (pH 6.0) for 6 months (ca. 11,000 pore volumes, PVs). Both columns effectively reduced NTO to the amine product, 3-amino-1,2,4-triazol-5-one (ATO). The column treating the pH-3.0 influent exhibited prolonged longevity in reducing NTO, treating 11-fold more PVs than the column treating pH-6.0 influent until the breakthrough point (defined as when 85% of NTO was removed). The exhausted columns (defined as when only 10% of NTO was removed) regained the NTO reducing capacity by reactivation using 1 M HCl, fully removing NTO. After the experiment, solid-phase analysis of the packed-bed material showed that ZVI was oxidized to iron (oxyhydr)oxide minerals such as magnetite, lepidocrocite, and goethite during NTO treatment. This is the first report on the reduction of NTO and the concomitant oxidation of ZVI in continuous-flow column experiments. The evidence indicates that treatment in a ZVI-packed bed reactor is an effective approach for the removal of NTO.
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Affiliation(s)
- Youngjae Yu
- Department of Chemical and Environmental Engineering, The University of Arizona, P.O. Box 210011, Tucson, AZ, 85721, USA
| | - Robert A Root
- Department of Environmental Science, The University of Arizona, Tucson, AZ, 85719, USA
| | - Reyes Sierra-Alvarez
- Department of Chemical and Environmental Engineering, The University of Arizona, P.O. Box 210011, Tucson, AZ, 85721, USA
| | - Jon Chorover
- Department of Environmental Science, The University of Arizona, Tucson, AZ, 85719, USA
| | - Jim A Field
- Department of Chemical and Environmental Engineering, The University of Arizona, P.O. Box 210011, Tucson, AZ, 85721, USA.
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Murillo-Gelvez J, Hickey K, Di Toro DM, Allen HE, Carbonaro RF, Chiu PC. Electron Transfer Energy and Hydrogen Atom Transfer Energy-Based Linear Free Energy Relationships for Predicting the Rate Constants of Munition Constituent Reduction by Hydroquinones. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:5284-5295. [PMID: 36961098 DOI: 10.1021/acs.est.2c08931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
No single linear free energy relationship (LFER) exists that can predict reduction rate constants of all munition constituents (MCs). To address this knowledge gap, we measured the reduction rates of MCs and their surrogates including nitroaromatics [NACs; 2,4,6-trinitrotoluene (TNT), 2,4-dinitroanisole (DNAN), 2-amino-4,6-dinitrotoluene (2-A-DNT), 4-amino-2,6-dinitrotoluene (4-A-DNT), and 2,4-dinitrotoluene (DNT)], nitramines [hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and nitroguanidine (NQ)], and azoles [3-nitro-1,2,4-triazol-5-one (NTO) and 3,4-dinitropyrazole (DNP)] by three dithionite-reduced quinones (lawsone, AQDS, and AQS). All MCs/NACs were reduced by the hydroquinones except NQ. Hydroquinone and MC speciations were varied by controlling pH, permitting the application of a speciation model to determine second-order rate constants (k) from observed pseudo-first-order rate constants. The intrinsic reactivity of MCs (oxidants) decreased upon deprotonation, while the opposite was true for hydroquinones (reductants). The rate constants spanned ∼6 orders of magnitude in the order NTO ≈ TNT > DNP > DNT ≈ DNAN ≈ 2-A-DNT > DNP- > 4-A-DNT > NTO- > RDX. LFERs developed using density functional theory-calculated electron transfer and hydrogen atom transfer energies and reported one-electron reduction potentials successfully predicted k, suggesting that these structurally diverse MCs/NACs are all reduced by hydroquinones through the same mechanism and rate-limiting step. These results increase the applicability of LFER models for predicting the fate and half-lives of MCs and related nitro compounds in reducing environments.
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Affiliation(s)
- Jimmy Murillo-Gelvez
- Department of Civil and Environmental Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Kevin Hickey
- Department of Civil and Environmental Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Dominic M Di Toro
- Department of Civil and Environmental Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Herbert E Allen
- Department of Civil and Environmental Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Richard F Carbonaro
- Department of Chemical Engineering, Manhattan College, Riverdale, New York 10471, United States
- Mutch Associates LLC, Ramsey, New Jersey 07446, United States
| | - Pei C Chiu
- Department of Civil and Environmental Engineering, University of Delaware, Newark, Delaware 19716, United States
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Rios-Valenciana EE, Menezes O, Romero J, Blubaum C, Krzmarzick MJ, Sierra-Alvarez R, Field JA. Elucidating the mechanisms associated with the anaerobic biotransformation of the emerging contaminant nitroguanidine. WATER RESEARCH 2023; 229:119496. [PMID: 36535085 DOI: 10.1016/j.watres.2022.119496] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/18/2022] [Accepted: 12/13/2022] [Indexed: 06/17/2023]
Abstract
Nitroguanidine (NQ) is a constituent of gas generators for automobile airbags, smokeless pyrotechnics, insecticides, propellants, and new insensitive munitions formulations applied by the military. During its manufacture and use, NQ can easily spread in soils, ground, and surface waters due to its high aqueous solubility. Very little is known about the microbial biotransformation of NQ. This study aimed to elucidate important mechanisms operating during NQ anaerobic biotransformation. To achieve this goal, we developed an anaerobic enrichment culture able to reduce NQ to nitrosoguanidine (NsoQ), which was further abiotically transformed to cyanamide. Effective electron donors for NQ biotransformation were lactate and, to a lesser extent, pyruvate. The results demonstrate that the enrichment process selected a sulfate-reducing culture that utilized lactate as its electron donor and sulfate as its electron acceptor while competing with NQ as an electron sink. A unique property of the culture was its requirement for exogenous nitrogen (e.g., from yeast extract or NH4Cl) for NQ biotransformation since NQ itself did not serve as a nitrogen source. The main phylogenetic groups associated with the NQ-reducing culture were sulfate-reducing and fermentative bacteria, namely Cupidesulfovibrio oxamicus (63.1% relative abundance), Dendrosporobacter spp. (12.0%), and Raoultibacter massiliens (10.9%). The molecular ecology results corresponded to measurable physiological properties of the most abundant members. The results establish the conditions for NQ anaerobic biotransformation and the microbial community associated with the process, improving our present comprehension of NQ environmental fate and assisting the development of NQ remediation strategies.
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Affiliation(s)
- Erika E Rios-Valenciana
- Department of Chemical and Environmental Engineering, The University of Arizona, P.O. Box 210011, Tucson, AZ 85721, United States
| | - Osmar Menezes
- Department of Chemical and Environmental Engineering, The University of Arizona, P.O. Box 210011, Tucson, AZ 85721, United States
| | - Jonathan Romero
- Department of Chemical and Environmental Engineering, The University of Arizona, P.O. Box 210011, Tucson, AZ 85721, United States
| | - Corey Blubaum
- Department of Chemical and Environmental Engineering, The University of Arizona, P.O. Box 210011, Tucson, AZ 85721, United States
| | - Mark J Krzmarzick
- School of Civil and Environmental Engineering, Oklahoma State University, Stillwater, OK 74078, United States
| | - Reyes Sierra-Alvarez
- Department of Chemical and Environmental Engineering, The University of Arizona, P.O. Box 210011, Tucson, AZ 85721, United States
| | - Jim A Field
- Department of Chemical and Environmental Engineering, The University of Arizona, P.O. Box 210011, Tucson, AZ 85721, United States.
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Rios-Valenciana EE, Menezes O, Niu XZ, Romero J, Root RA, Chorover J, Sierra-Alvarez R, Field JA. Reductive transformation of the insensitive munitions compound nitroguanidine by different iron-based reactive minerals. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 309:119788. [PMID: 35843454 DOI: 10.1016/j.envpol.2022.119788] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
Nitroguanidine (NQ) is an emerging contaminant being used by the military as a constituent of new insensitive munitions. NQ is also used in rocket propellants, smokeless pyrotechnics, and vehicle restraint systems. Its uncontrolled transformation in the environment can generate toxic and potentially mutagenic products, posing hazards that need to be remediated. NQ transformation has only been investigated to a limited extent. Thus, it is crucial to expand the narrow spectrum of NQ remediation strategies and understand its transformation pathways and end products. Iron-based reactive minerals should be investigated for NQ treatment because they are successfully used in existing technologies, such as permeable reactive barriers, for treating a wide range of organic pollutants. This study tested the ability of micron-sized zero-valent iron (m-ZVI), mackinawite, and commercial FeS, to transform NQ under anoxic conditions. NQ transformation followed pseudo-first-order kinetics. The reaction rate constants decreased as follows: commercial FeS > mackinawite > m-ZVI. For the assessed minerals, the NQ transformation started with the reduction of the nitro group forming nitrosoguanidine (NsoQ). Then, aminoguanidine (AQ) was accumulated during the reaction of NQ with m-ZVI, accounting for 86% of the nitrogen mass recovery. When NQ was reacted with commercial FeS, 45% and 20% of nitrogen were recovered as AQ and guanidine, respectively, after 24 h. Nonetheless, NsoQ persisted, contributing to the N-balance. When mackinawite was present, NsoQ disappeared, but AQ was not detected, and guanidine accounted for 11% of the nitrogen recovery. AQ was ultimately transformed into cyanamide, whose dimerization triggered the formation of cyanoguanidine. Alternatively, NsoQ was transformed into guanidine, which reacted with cyanamide to form biguanide. This is the first report systematically investigating the NQ transformation by different iron-based reactive minerals. The evidence indicates that these minerals are attractive alternatives for developing NQ remediation strategies.
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Affiliation(s)
- Erika E Rios-Valenciana
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, P.O. Box 210011, AZ, 85721, USA
| | - Osmar Menezes
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, P.O. Box 210011, AZ, 85721, USA
| | - Xi-Zhi Niu
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, P.O. Box 210011, AZ, 85721, USA
| | - Jonathan Romero
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, P.O. Box 210011, AZ, 85721, USA
| | - Robert A Root
- Department of Environmental Science, The University of Arizona, Tucson, AZ, 85721, USA
| | - Jon Chorover
- Department of Environmental Science, The University of Arizona, Tucson, AZ, 85721, USA
| | - Reyes Sierra-Alvarez
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, P.O. Box 210011, AZ, 85721, USA
| | - Jim A Field
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, P.O. Box 210011, AZ, 85721, USA.
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Menezes O, Kocaman K, Wong S, Rios-Valenciana EE, Baker EJ, Hatt JK, Zhao J, Madeira CL, Krzmarzick MJ, Spain JC, Sierra-Alvarez R, Konstantinidis KT, Field JA. Quinone Moieties Link the Microbial Respiration of Natural Organic Matter to the Chemical Reduction of Diverse Nitroaromatic Compounds. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:9387-9397. [PMID: 35704431 DOI: 10.1021/acs.est.2c01329] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Insensitive munitions compounds (IMCs) are emerging nitroaromatic contaminants developed by the military as safer-to-handle alternatives to conventional explosives. Biotransformation of nitroaromatics via microbial respiration has only been reported for a limited number of substrates. Important soil microorganisms can respire natural organic matter (NOM) by reducing its quinone moieties to hydroquinones. Thus, we investigated the NOM respiration combined with the abiotic reduction of nitroaromatics by the hydroquinones formed. First, we established nitroaromatic concentration ranges that were nontoxic to the quinone respiration. Then, an enrichment culture dominated by Geobacter anodireducens could indirectly reduce a broad array of nitroaromatics by first respiring NOM components or the NOM surrogate anthraquinone-2,6-disulfonate (AQDS). Without quinones, no nitroaromatic tested was reduced except for the IMC 3-nitro-1,2,4-triazol-5-one (NTO). Thus, the quinone respiration expanded the spectrum of nitroaromatics susceptible to transformation. The system functioned with very low quinone concentrations because NOM was recycled by the nitroaromatic reduction. A metatranscriptomic analysis demonstrated that the microorganisms obtained energy from quinone or NTO reduction since respiratory genes were upregulated when AQDS or NTO was the electron acceptor. The results indicated microbial NOM respiration sustained by the nitroaromatic-dependent cycling of quinones. This process can be applied as a nitroaromatic remediation strategy, provided that a quinone pool is available for microorganisms.
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Affiliation(s)
- Osmar Menezes
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Kumru Kocaman
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Stanley Wong
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Erika E Rios-Valenciana
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Eliot J Baker
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Janet K Hatt
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Jianshu Zhao
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30318, United States
| | - Camila L Madeira
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Mark J Krzmarzick
- School of Civil and Environmental Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Jim C Spain
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Center for Environmental Diagnostics & Bioremediation, University of West Florida, Pensacola, Florida 32514, United States
| | - Reyes Sierra-Alvarez
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Konstantinos T Konstantinidis
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Jim A Field
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, United States
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Menezes O, Owens C, Rios-Valenciana EE, Sierra-Alvarez R, Field JA, Spain JC. Designing bacterial consortia for the complete biodegradation of insensitive munitions compounds in waste streams. Biotechnol Bioeng 2022; 119:2437-2446. [PMID: 35706349 DOI: 10.1002/bit.28160] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/24/2022] [Accepted: 06/13/2022] [Indexed: 11/08/2022]
Abstract
Insensitive munitions compounds (IMCs), such as 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO), are replacing conventional explosives in munitions formulations. Manufacture and use of IMCs generate waste streams in manufacturing plants and load/assemble/pack facilities. There is a lack of practical experience in executing biodegradation strategies to treat IMCs waste streams. This study establishes a proof-of-concept that bacterial consortia can be designed to mineralize IMCs and co-occurring nitroaromatics in waste streams. First, DNAN, 4-nitroanisole (4-NA), and 4-chloronitrobenzene (4-CNB) in a synthetic DNAN-manufacturing waste stream were biodegraded using an aerobic fluidized-bed reactor (FBR) inoculated with Nocardioides sp. JS 1661 (DNAN degrader), Rhodococcus sp. JS 3073 (4-NA degrader), and Comamonadaceae sp. LW1 (4-CNB degrader). No biodegradation was detected when the FBR was operated under anoxic conditions. Second, DNAN and NTO were biodegraded in a synthetic load/assemble/pack waste stream during a sequential treatment comprising: (i) aerobic DNAN biodegradation in the FBR; (ii) anaerobic NTO biotransformation to 3-amino-1,2,4-triazol-5-one (ATO) by an NTO-respiring enrichment; and (iii) aerobic ATO mineralization by an ATO-oxidizing enrichment. Complete biodegradation relied on switching redox conditions. The results provide the basis for designing consortia to treat mixtures of IMCs and related waste products by incorporating microbes with the required catabolic capabilities.
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Affiliation(s)
- Osmar Menezes
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona, USA
| | - Cameron Owens
- Center for Environmental Diagnostics and Bioremediation, University of West Florida, Pensacola, Florida, USA
| | - Erika E Rios-Valenciana
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona, USA
| | - Reyes Sierra-Alvarez
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona, USA
| | - Jim A Field
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona, USA
| | - Jim C Spain
- Center for Environmental Diagnostics and Bioremediation, University of West Florida, Pensacola, Florida, USA.,School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
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Xin D, Girón J, Fuller ME, Chiu PC. Abiotic reduction of 3-nitro-1,2,4-triazol-5-one (NTO) and other munitions constituents by wood-derived biochar through its rechargeable electron storage capacity. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:316-329. [PMID: 35050280 DOI: 10.1039/d1em00447f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The environmental fate of 3-nitro-1,2,4-triazol-5-one (NTO) and other insensitive munitions constituents (MCs) is of significant concern due to their high water solubility and mobility relative to legacy MCs. Plant-based biochars have been shown to possess a considerable electron storage capacity (ESC), which enables them to undergo reversible electron transfer reactions. We hypothesized biochar can act as a rechargeable electron donor to effect abiotic reduction of MCs repeatedly through its ESC. To test this hypothesis, MC reduction experiments were performed using wood-derived biochars that were oxidized with dissolved oxygen or reduced with dithionite. Removal of aqueous NTO, an anion at circumneutral pH, by oxidized biochar was minimal and occurred through reversible adsorption. In contrast, NTO removal by reduced biochar was much more pronounced and occurred predominantly through reduction, with concomitant formation of 3-amino-1,2,4-triazol-5-one (ATO). Mass balance and electron recovery with ferricyanide further showed that (1) the amount of NTO reduced to ATO was relatively constant (85-100 μmol per gram of biochar) at pH 6-10; (2) the fraction of biochar ESC reactive toward NTO was ca. 30% of that toward ferricyanide; (3) the NTO-reactive fraction of the ESC was regenerable over multiple redox cycles. We also evaluated biochar transformation of other MCs, including nitroguanidine (NQ), 2,4-dinitroanisole (DNAN), and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). While mass and electron balances could not be established due to sorption, DNAN and RDX reduction by reduced biochar was confirmed via detection of multiple reduction products. In contrast, NQ was not reduced under any of the conditions tested. This study is the first demonstration of organic contaminant degradation through biochar's rechargeable ESC. Our results indicate biochar is a regenerable electron storage medium and sorbent that can remove MCs from water through concurrent reduction and sorption, and is thus potentially useful for pollution control and remediation at military facilities.
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Affiliation(s)
- Danhui Xin
- Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716, USA.
| | - Julián Girón
- Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716, USA.
| | - Mark E Fuller
- Aptim Federal Services, 17 Princess Road, Lawrenceville, NJ 08648, USA.
| | - Pei C Chiu
- Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716, USA.
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