Enhanced coagulation and oxidation by the Mn(VII)-Fe(III)/peroxymonosulfate process: Performance and mechanisms

Zheng-Yu Dong; Yi-Li Lin; Tian-Yang Zhang; Chen-Yan Hu; Yang Pan; Renjie Pan; Yu-Lin Tang; Bin Xu; Nai-Yun Gao

doi:10.1016/j.watres.2022.119200

Enhanced coagulation and oxidation by the Mn(VII)-Fe(III)/peroxymonosulfate process: Performance and mechanisms

Water Res. 2022 Nov 1:226:119200. doi: 10.1016/j.watres.2022.119200. Epub 2022 Oct 3.

Authors

Zheng-Yu Dong¹, Yi-Li Lin², Tian-Yang Zhang¹, Chen-Yan Hu³, Yang Pan⁴, Renjie Pan¹, Yu-Lin Tang¹, Bin Xu⁵, Nai-Yun Gao⁶

Affiliations

¹ State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
² Department of Safety, Health and Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 824, Taiwan, ROC.
³ College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, PR China.
⁴ State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
⁵ State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China. Electronic address: tjwenwu@tongji.edu.cn.
⁶ State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.

PMID: 36257154
DOI: 10.1016/j.watres.2022.119200

Abstract

To improve the performance of the conventional coagulation process, a permanganate (Mn(VII)) pre-oxidation combined with Fe(III)/peroxymonosulfate (PMS) coagulation process (Mn(VII)-Fe(III)/PMS) that can significantly improve the removal of dissolved organic carbon (DOC), turbidity, and micropollutants is proposed in this study. Compared with conventional Fe(III) coagulation, the Mn(VII)-Fe(III)/PMS process can also significantly enhance the removal of iohexol and sulfamethoxazole in raw water. During this process, the primary reduction product, Mn(IV), after Mn(VII) pre-oxidation was adsorbed on the floc surfaces and involved in the Fe(III)/PMS process. The natural organic matter (NOM) in raw water mediated the redox cycle of iron. The synergistic effect of NOM, Fe, and Mn facilitated the redox cycle of Mn(III)/Mn(IV) and Fe(III)/Fe(II) to promote the activation of PMS. The sulfate radical (SO₄^•-) played an important role in the degradation of micropollutants. The formation potential of the detected volatile disinfection by-product (DBP) during the subsequent chlorination was reduced by 21.9% after the Mn(VII)-Fe(III)/PMS process. This study demonstrated the promising application of the Mn(VII)-Fe(III)/PMS process for coagulation and micropollutant control and illustrated the reaction mechanism. This study provides guidance for improving conventional drinking water treatment processes.

Keywords: Coagulation; Micropollutants; Oxidation; Peroxymonosulfate; Synergistic effect.

MeSH terms

Ferric Compounds*
Oxidation-Reduction
Peroxides
Water Purification*

Substances

peroxymonosulfate
Ferric Compounds
Peroxides