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Lu X, Zhou X, Qiu W, Wang Z, Wang Y, Zhang H, Yu J, Wang D, Gu J, Ma J. Kinetics and mechanism of the reaction of hydrogen peroxide with hypochlorous acid: Implication on electrochemical water treatment. JOURNAL OF HAZARDOUS MATERIALS 2022; 438:129420. [PMID: 35816805 DOI: 10.1016/j.jhazmat.2022.129420] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 06/03/2022] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
Reduction of HOCl to Cl- by in-situ electrochemical synthesis or ex-situ addition of H2O2 is a feasible method to minimize Cl-DBPs and ClOx- (x = 2, 3, and 4) formation in electrochemical oxidative water treatment systems. This work has investigated the kinetics and mechanism of the reaction between H2O2 and HOCl. The kinetics study showed the species-specific second order rate constants for HOCl with H2O2 (k1), HOCl with HO2- (k2) and OCl- with H2O2 (k3) are 195.5 ± 3.3 M-1s-1, 4.0 × 107 M-1s-1 and 3.5 × 103 M-1s-1, respectively. The density functional theory calculation showed k2 is the most advantageous thermodynamically pathway because it does not need to overcome a high energy barrier. The yields of 1O2 generation from the reaction of H2O2 with HOCl were reinvestigated by using furfuryl alcohol (FFA) as a probe, and an average of 92.3% of 1O2 yields was obtained at pH 7-12. The second order rate constants of the reaction of 1O2 with 13 phenolates were determined by using the H2O2/HOCl system as a quantitative 1O2 production source. To establish a quantitative structure activity relationship, quantum chemical descriptors were more satisfactory than empirical Hammett constants. The potential implications in electrochemical oxidative water treatment were discussed at the end.
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Affiliation(s)
- Xiaohui Lu
- State Key Laboratory of Urban Water Resource and Environment, School of Environmental, Harbin Institute of Technology, Harbin 150090, China
| | - Xiaoqun Zhou
- State Key Laboratory of Urban Water Resource and Environment, School of Environmental, Harbin Institute of Technology, Harbin 150090, China
| | - Wei Qiu
- State Key Laboratory of Urban Water Resource and Environment, School of Environmental, Harbin Institute of Technology, Harbin 150090, China.
| | - Ziyue Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environmental, Harbin Institute of Technology, Harbin 150090, China
| | - Yishi Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environmental, Harbin Institute of Technology, Harbin 150090, China
| | - Haochen Zhang
- State Key Laboratory of Urban Water Resource and Environment, School of Environmental, Harbin Institute of Technology, Harbin 150090, China
| | - Jiaxin Yu
- State Key Laboratory of Urban Water Resource and Environment, School of Environmental, Harbin Institute of Technology, Harbin 150090, China
| | - Da Wang
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Jia Gu
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Jun Ma
- State Key Laboratory of Urban Water Resource and Environment, School of Environmental, Harbin Institute of Technology, Harbin 150090, China.
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Effect of pH on Escherichia coli Removal by Electrocoagulation and Elimination Kinetics after Treatment. J CHEM-NY 2022. [DOI: 10.1155/2022/5249368] [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
There are different techniques for removing microorganisms in wastewater, each with its own advantages and disadvantages. Electrocoagulation because of its simplicity has gained great attention and is used for the removal of various ions, organic matters, and microorganisms. In this study, the effectiveness and mechanism of Escherichia coli (E. coli) removal by electrocoagulation process using aluminum and ordinary steel electrodes at different initial-pH and the kinetics of elimination of E. coli in solution after treatment were investigated. Artificial wastewater contaminated by E. coli culture was used in the experiments. The results show that the initial-pH influences significantly the effectiveness of E. coli removal. Under the experimental conditions used, more than 5 log removal of E. coli is obtained, irrespective of the nature of the electrode (ordinary steel or aluminum) and the value of the initial pH. On the one hand, the best rates of elimination are obtained for solutions that are slightly acidic (pH 5.5) and for an alkaline pH (8.5 and 10). On the other hand, the elimination decreases for a neutral solution and for a very acidic solution (pH 2.9) because of the strong resistance developed by E. coli at those pH values. For optimal treatment, the choice of electrode material depends on the initial pH. Furthermore, the study of the kinetics of elimination of E. coli after treatment shows the remanent power of the electrocoagulation process. It allows reducing treatment time and energy consumption, thus reducing the cost of treatment.
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Isidro J, Sáez C, Llanos J, Lobato J, Cañizares P, Matthée T, Rodrigo MA. Adapting the low-cost pre-disinfection column PREDICO for simultaneous softening and disinfection of pore water. CHEMOSPHERE 2022; 287:132334. [PMID: 34563766 DOI: 10.1016/j.chemosphere.2021.132334] [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: 06/01/2021] [Revised: 09/17/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Abstract
In previous works, a low-cost predisinfection column that combined coagulation-flocculation and GAC filtration was proposed for combination with electrodisinfection in the successful treatment of highly faecal polluted surface water. In this work, this column is adapted for the treatment of pore water by transforming the coagulation chamber into a chemical reactor with lime and replacing the GAC of the filter with ion exchange resins. This adapted system can soften water, remove nitrate and condition water for very efficient electrochemical disinfection, where 4 logs and 3 logs in the removal of E. coli and P. aeruginosa, respectively, were reached using commercial electrochemical cells, i.e., CabECO ® or MIKROZON®. The availability and low cost of the technology are strong points for usage in poor areas of developing countries.
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Affiliation(s)
- J Isidro
- Chemical Engineering Department, Faculty of Chemical Sciences and Technologies, University of Castilla-La Mancha, Edificio Enrique Costa Novella, Campus Universitario s/n, 13005, Ciudad Real, Spain
| | - C Sáez
- Chemical Engineering Department, Faculty of Chemical Sciences and Technologies, University of Castilla-La Mancha, Edificio Enrique Costa Novella, Campus Universitario s/n, 13005, Ciudad Real, Spain.
| | - J Llanos
- Chemical Engineering Department, Faculty of Chemical Sciences and Technologies, University of Castilla-La Mancha, Edificio Enrique Costa Novella, Campus Universitario s/n, 13005, Ciudad Real, Spain
| | - J Lobato
- Chemical Engineering Department, Faculty of Chemical Sciences and Technologies, University of Castilla-La Mancha, Edificio Enrique Costa Novella, Campus Universitario s/n, 13005, Ciudad Real, Spain
| | - P Cañizares
- Chemical Engineering Department, Faculty of Chemical Sciences and Technologies, University of Castilla-La Mancha, Edificio Enrique Costa Novella, Campus Universitario s/n, 13005, Ciudad Real, Spain
| | - T Matthée
- CONDIAS GmbH, Fraunhoferstraße 1b, 25524, Itzehoe, Germany
| | - M A Rodrigo
- Chemical Engineering Department, Faculty of Chemical Sciences and Technologies, University of Castilla-La Mancha, Edificio Enrique Costa Novella, Campus Universitario s/n, 13005, Ciudad Real, Spain
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Rodríguez-Peña M, Barrios Pérez J, Llanos J, Saez C, Barrera-Díaz C, Rodrigo M. Electrochemical generation of ozone using a PEM electrolyzer at acidic pHs. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.118672] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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