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Elimination kinetics and detoxification mechanisms of microcystin-LR during UV/Chlorine process.
Chemosphere. 2019 Jan; 214:702-709.C

Abstract

Microcystin-LR (MC-LR), a toxin produced by cyanobacteria, is very toxic and poses a threat to public health when entering water treatment works. In this study, UV/chlorine process, as an advanced oxidation process (AOP), has been demonstrated for effective elimination of MC-LR levels and associated toxicity. At a chlorine dose of 3.0 mg L-1 and UV fluence of 125 mJ cm-2, MC-LR (initial concentration 1.0 μM) was reduced by 92.5%, which was much higher than 20.3% removal under UV irradiation alone and 65.1% removal during dark chlorination. Enhanced degradation was attributed by hydroxyl radicals (HO) and reactive chlorine species (RCS), mainly Cl2- and ClO. Increasing chlorine doses or lowering pH favored MC-LR removal. Increased bicarbonate and natural organic matter concentrations inhibited MC-LR removal, but bromide ions enhanced MC-LR removal instead. MC-LR elimination rates in natural waters were roughly two times smaller than those in ultrapure water. The reactive radicals promoted hydroxylation of both diene of Adda moiety and double bond of Mdha moiety in MC-LR. UV exposure enhanced the dechlorination of chloro-MC-LR via the cleavage of CCl bond. The toxicity was evaluated by a protein phosphatase (PP2A) inhibition assay. At a chlorine dose of 3.0 mg L-1 and UV fluence of 125 mJ cm-2, the toxicity of the treated water was reduced by 75.0%, which was also higher than 25.7% and 46.7% removal under UV irradiation alone and during dark chlorination, respectively. These results highlight UV/chlorine is an efficient AOP for MC-LR degradation and detoxification.

Authors+Show Affiliations

School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China.School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China.School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China.School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China. Electronic address: yangx36@mail.sysu.edu.cn.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

30293023

Citation

Zhang, Xinran, et al. "Elimination Kinetics and Detoxification Mechanisms of microcystin-LR During UV/Chlorine Process." Chemosphere, vol. 214, 2019, pp. 702-709.
Zhang X, He J, Xiao S, et al. Elimination kinetics and detoxification mechanisms of microcystin-LR during UV/Chlorine process. Chemosphere. 2019;214:702-709.
Zhang, X., He, J., Xiao, S., & Yang, X. (2019). Elimination kinetics and detoxification mechanisms of microcystin-LR during UV/Chlorine process. Chemosphere, 214, 702-709. https://doi.org/10.1016/j.chemosphere.2018.09.162
Zhang X, et al. Elimination Kinetics and Detoxification Mechanisms of microcystin-LR During UV/Chlorine Process. Chemosphere. 2019;214:702-709. PubMed PMID: 30293023.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Elimination kinetics and detoxification mechanisms of microcystin-LR during UV/Chlorine process. AU - Zhang,Xinran, AU - He,Jun, AU - Xiao,Shuqi, AU - Yang,Xin, Y1 - 2018/09/29/ PY - 2018/06/27/received PY - 2018/09/23/revised PY - 2018/09/28/accepted PY - 2018/10/8/pubmed PY - 2019/1/12/medline PY - 2018/10/8/entrez KW - Advanced oxidation process KW - Microcystin-LR KW - Toxicity KW - UV/chlorine KW - Water treatment SP - 702 EP - 709 JF - Chemosphere JO - Chemosphere VL - 214 N2 - Microcystin-LR (MC-LR), a toxin produced by cyanobacteria, is very toxic and poses a threat to public health when entering water treatment works. In this study, UV/chlorine process, as an advanced oxidation process (AOP), has been demonstrated for effective elimination of MC-LR levels and associated toxicity. At a chlorine dose of 3.0 mg L-1 and UV fluence of 125 mJ cm-2, MC-LR (initial concentration 1.0 μM) was reduced by 92.5%, which was much higher than 20.3% removal under UV irradiation alone and 65.1% removal during dark chlorination. Enhanced degradation was attributed by hydroxyl radicals (HO) and reactive chlorine species (RCS), mainly Cl2- and ClO. Increasing chlorine doses or lowering pH favored MC-LR removal. Increased bicarbonate and natural organic matter concentrations inhibited MC-LR removal, but bromide ions enhanced MC-LR removal instead. MC-LR elimination rates in natural waters were roughly two times smaller than those in ultrapure water. The reactive radicals promoted hydroxylation of both diene of Adda moiety and double bond of Mdha moiety in MC-LR. UV exposure enhanced the dechlorination of chloro-MC-LR via the cleavage of CCl bond. The toxicity was evaluated by a protein phosphatase (PP2A) inhibition assay. At a chlorine dose of 3.0 mg L-1 and UV fluence of 125 mJ cm-2, the toxicity of the treated water was reduced by 75.0%, which was also higher than 25.7% and 46.7% removal under UV irradiation alone and during dark chlorination, respectively. These results highlight UV/chlorine is an efficient AOP for MC-LR degradation and detoxification. SN - 1879-1298 UR - https://www.unboundmedicine.com/medline/citation/30293023/Elimination_kinetics_and_detoxification_mechanisms_of_microcystin_LR_during_UV/Chlorine_process_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0045-6535(18)31828-9 DB - PRIME DP - Unbound Medicine ER -