In situ acid production by organic matter induced with trace homogeneous Fenton reagent for membrane fouling control

Rui Miao; Haoxue Ran; Yifan Yang; Yanfei Li; Zhuowen Ma; Yongtao Lv; Xiaorong Meng; Miaolu He; Lei Wang

doi:10.1016/j.watres.2024.121752

In situ acid production by organic matter induced with trace homogeneous Fenton reagent for membrane fouling control

Water Res. 2024 May 8:258:121752. doi: 10.1016/j.watres.2024.121752. Online ahead of print.

Authors

Rui Miao¹, Haoxue Ran², Yifan Yang², Yanfei Li², Zhuowen Ma², Yongtao Lv¹, Xiaorong Meng¹, Miaolu He¹, Lei Wang³

Affiliations

¹ Key Laboratory of Membrane Separation of Shaanxi Province, Key Laboratory of Northwest Water Resources, Key Laboratory of Environmental Engineering of Shaanxi Province, Xi'an University of Architecture and Technology, Yan Ta Road No. 13, Xi'an 710055, China; Research Institute of Membrane Separation Technology of Shaanxi Province, Xi'an University of Architecture and Technology, Yan Ta Road No. 13, Xi'an 710055, China.
² Key Laboratory of Membrane Separation of Shaanxi Province, Key Laboratory of Northwest Water Resources, Key Laboratory of Environmental Engineering of Shaanxi Province, Xi'an University of Architecture and Technology, Yan Ta Road No. 13, Xi'an 710055, China.
³ Key Laboratory of Membrane Separation of Shaanxi Province, Key Laboratory of Northwest Water Resources, Key Laboratory of Environmental Engineering of Shaanxi Province, Xi'an University of Architecture and Technology, Yan Ta Road No. 13, Xi'an 710055, China; Research Institute of Membrane Separation Technology of Shaanxi Province, Xi'an University of Architecture and Technology, Yan Ta Road No. 13, Xi'an 710055, China. Electronic address: wl0178@126.com.

PMID: 38761591
DOI: 10.1016/j.watres.2024.121752

Abstract

The homogeneous Fenton process involves both coagulation and oxidation, but it requires added acidity, so it is rarely used to control membrane fouling. This work found that the pH of neutral simulated wastewater sharply declined to 4.1 after pre-treatment with 0.1 mM Fenton reagent (Fe²⁺:H₂O₂=1:1) without added acidity. This occurred mainly because the trace homogeneous Fenton reagent induced in situ acid production by organic matter in the wastewater, which supplied the acidic conditions required for the Fenton reaction and ensured that the reaction could proceed continuously. Then, oxidation during the pre-Fenton process enhanced the electrostatic repulsion forces and effectively weakened the hydrogen bonds of organic matter at the membrane surface by altering the net charge and hydroxyl content of organic matter, while coagulation caused the foulants to gather and form large aggregates. These changes diminished the deposition of foulants onto the membrane surface and resulted in a looser fouling layer, which eventually caused the membrane fouling rate to decline from 83 % to 24 % and the flux recovery rate to increase from 44 % to 98 % during 2 h of filtration. This membrane fouling mitigation ability is much superior to that of pre-H₂O₂, pre-Fe²⁺ or pre-Fe³⁺ processes with equivalent doses.

Keywords: In situ acid production; Mitigation mechanism; Organic fouling; Trace amounts of homogeneous fenton reagent; Ultrafiltration membrane.