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Chen H, Lin T, Wang P, Zhang X, Jiang F, Liu W. Treatment of bromate in UV/sulfite autoxidation process enhances formation of dibromoacetonitrile during chlorination. WATER RESEARCH 2022; 225:119207. [PMID: 36215832 DOI: 10.1016/j.watres.2022.119207] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 09/28/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
The integration of UV/sulfite autoxidation process (USAP, i.e., UV activation of sulfite in the presence of 5 ∼ 10 mg/L O2) into conventional water to degrade micropollutants rises extensive attention, but its impact on water quality, and especially the formation of disinfection byproducts is still unclear. Herein, the formation of dibromoacetonitrile (DBAN) from bromate (BrO3-) upon treatment with USAP followed by chlorination was evaluated, in the presence of amino acids (AAs) selected as representative organic matter in drinking water. Results revealed that hydrated electrons (eaq-) produced during USAP contribute to the reduction of BrO3- to Br-, which is then converted into HBrO/BrO- during post-chlorination. At the same time, sulfate radicals (SO4•-) and hydroxyl radicals (•OH) generated in USAP mediated AAs' conversion via α-hydrogen abstraction and NH2-hydrogen abstraction reactions to produce HN=C(CH3)‒COOH, CH3‒CH=NH, and CH3‒CN, which are released into the post-chlorination stage and therefore, enhance the bromine utilization factor (BUF) value and DBAN formation. The effects of the USAP treatment time, BrO3- concentration, AA concentration, pH, and real waters were also evaluated. Although 63.5% of BrO3- was eliminated by USAP followed by chlorination, the toxicity index (TI) was increased by 1.5-fold due to the formation of the all brominated CX3R-type nitrogenous disinfection byproducts (N-DBPs), demonstrating the potential risk of applying USAP as a treatment process in BrO3- containing waters.
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Affiliation(s)
- Han Chen
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Tao Lin
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China.
| | - Peifang Wang
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China.
| | - Xue Zhang
- Suzhou Water Supply Company Limited, Suzhou 215002, PR China
| | - Fuchun Jiang
- Suzhou Water Supply Company Limited, Suzhou 215002, PR China
| | - Wei Liu
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
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Engineering of Nanostructured Carbon Catalyst Supports for the Continuous Reduction of Bromate in Drinking Water. Mol Vis 2022. [DOI: 10.3390/c8020021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Recent works in the development of nanostructured catalysts for bromate reduction in drinking water under hydrogen have highlighted the importance of the properties of the metallic phase support in their overall performance. Since most works in catalyst development are carried out in powder form, there is an overlooked gap in the correlation between catalyst support properties and performance in typical continuous applications such as fixed bed reactors. In this work, it is shown that the mechanical modification of commercially available carbon nanotubes, one of the most promising supports, can significantly enhance the activity of the catalytic system when tested in a stirred tank reactor, but upon transition to a fixed bed reactor, the formation of preferential pathways for the liquid flow and high pressure drops were observed. This effect could be minimized by the addition of an inert filler to increase the bed porosity; however, the improvement in catalytic performance when compared with the as-received support material was not retained. The operation of the continuous catalytic system was then optimized using a 1 wt.% Pd catalyst supported on the as-received carbon nanotubes. Effluent and hydrogen flow rates as well as catalyst loadings were systematically optimized to find an efficient set of parameters for the operation of the system, regarding its catalytic performance, capacity to treat large effluent flows, and minimization of catalyst and hydrogen requirements. Experiments carried out in the presence of distilled water as a reaction medium demonstrate that bromate can be efficiently removed from the liquid phase, whereas when using a real water matrix, a tendency for the deactivation of the catalyst over time was more apparent throughout 200 flow passages over the catalytic bed, which was mostly attributed to the competitive adsorption of inorganic matter on the catalyst active centers, or the formation of mineral deposits blocking access to the catalyst.
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Chen H, Lin T, Yan X, Xu H. Elevated risk of haloacetonitrile formation during post-chlorination when applying sulfite/UV advanced reduction technology to eliminate bromate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150612. [PMID: 34597579 DOI: 10.1016/j.scitotenv.2021.150612] [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: 05/25/2021] [Revised: 09/19/2021] [Accepted: 09/22/2021] [Indexed: 06/13/2023]
Abstract
The formation of haloacetonitriles (HANs) during chlorination after sulfite/ultraviolet (UV) treatment of bromate (BrO3-) in the presence of amino acids (AAs) was investigated. During sulfite/UV treatment, the primary species hydrated electrons (eaq-) and hydrogen atom radicals (H) dominated the reduction of BrO3- to bromide (Br-), whereas the sulfite anion radicals (SO3-) and H degraded AAs to produce the intermediates HN=C(CH3)-COOH, CH3-CH=NH, and CH3-C≡N via α‑hydrogen abstraction and NH2-hydrogen abstraction mechanisms. During post-chlorination, Br- was converted to HBrO/BrO-, and the HN=C(CH3)-COOH, CH3-CH=NH, and CH3-C≡N groups featured higher bromine utilization factor (BUF) and chlorine utilization factor (CUF) values than AAs, enhancing the formation of dibromoacetonitrile (DBAN) and dichloroacetonitrile (DCAN). The energetic feasibility of the transformation pathway, that is, HN=C(CH3)-COOH, CH3-CH=NH, and CH3-C ≡ N formation via hydrogen abstraction by SO3- and H and their further conversion to HANs, was proved by density functional theory calculations, which showed stepwise negative Gibbs free energy changes (ΔG < 0). The effects of pH and water matrices (e.g., HCO3-, Cl-, Fe3+, and natural organic matter) were comprehensively evaluated. Although 72% of BrO3- was removed by sulfite/UV treatment in the presence of AAs, the cytotoxicity index (CTI) and genotoxicity index (GTI) during post-chlorination increased by 213% and 125%, respectively, due to the formation of 24 CX3R-type disinfection by-products (DBPs), especially brominated DBPs. Accordingly, more attention should be given to the formation of brominated DBPs during post-chlorination when using sulfite/UV processes to remove BrO3- in the presence of AAs. As a solution, using monochloramine instead of chlorine as a disinfectant after the sulfite/UV process could significantly lower the CTI and GTI values by alleviating the formation of brominated DBPs.
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Affiliation(s)
- Han Chen
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Tao Lin
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China.
| | - Xiaoshu Yan
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Hang Xu
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
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Hussain A, Rehman F, Rafeeq H, Waqas M, Asghar A, Afsheen N, Rahdar A, Bilal M, Iqbal HMN. In-situ, Ex-situ, and nano-remediation strategies to treat polluted soil, water, and air - A review. CHEMOSPHERE 2022; 289:133252. [PMID: 34902385 DOI: 10.1016/j.chemosphere.2021.133252] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/02/2021] [Accepted: 12/09/2021] [Indexed: 02/05/2023]
Abstract
Nanotechnology, as an emerging science, has taken over all fields of life including industries, health and medicine, environmental issues, agriculture, biotechnology etc. The use of nanostructure molecules has revolutionized all sectors. Environmental pollution is a great concern now a days, in all industrial and developing as well as some developed countries. A number of remedies are in practice to overcome this problem. The application of nanotechnology in the bioremediation of environmental pollutants is a step towards revolution. The use of various types of nanoparticles (TiO2 based NPs, dendrimers, Fe based NPs, Silica and carbon nanomaterials, Graphene based NPs, nanotubes, polymers, micelles, nanomembranes etc.) is in practice to diminish environmental hazards. For this many In-situ (bioventing, bioslurping, biosparging, phytoremediation, permeable reactive barrier etc.) and Ex-situ (biopile, windrows, bioreactors, land farming etc.) methodologies are employed. Improved properties like nanoscale size, less time utilization, high adaptability for In-situ and Ex-situ use, undeniable degree of surface-region to-volume proportion for possible reactivity, and protection from ecological elements make nanoparticles ideal for natural applications. There are distinctive nanomaterials and nanotools accessible to treat the pollutants. Each of these methods and nanotools depends on the properties of foreign substances and the pollution site. The current designed review highlights the techniques used for bioremediation of environmental pollutants as well as use of various nanoparticles along with proposed In-situ and Ex-situ bioremediation techniques.
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Affiliation(s)
- Asim Hussain
- Department of Biochemistry, University of Agriculture, Faisalabad, 38000, Pakistan
| | - Fazeelat Rehman
- Department of Chemistry, School of Natural Sciences, National University of Sciences & Technology, Islamabad 44000, Pakistan
| | - Hamza Rafeeq
- Department of Biochemistry, Riphah International University, Faisalabad, 38000, Pakistan
| | - Muhammad Waqas
- Department of Applied Sciences, National Textile University Faisalabad, 37610, Pakistan
| | - Asma Asghar
- Department of Biochemistry, University of Agriculture, Faisalabad, 38000, Pakistan
| | - Nadia Afsheen
- Department of Biochemistry, Riphah International University, Faisalabad, 38000, Pakistan
| | - Abbas Rahdar
- Department of Physics, University of Zabol, Zabol, P. O. Box. 98613-35856, Iran
| | - Muhammad Bilal
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an 223003, China.
| | - Hafiz M N Iqbal
- Tecnologico de Monterrey, School of Engineering and Sciences, Monterrey, 64849, Mexico.
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