{"title":"High-efficiency degradation of nanofiltration concentrates using an iron-modified self-breathing electrode in electro-Fenton systems","authors":"Hongyun Ren, Zilong Zhang, Xia Qin, Cuicui Xu, Fanbin Zhang, Xiyang Li, Xingwei Tao, Xujie Lan","doi":"10.1016/j.jwpe.2025.107480","DOIUrl":null,"url":null,"abstract":"<div><div>The homogeneous electro-Fenton(EF) technique is widely recognized in water treatment for its efficient generation of hydroxyl radicals (·OH). However, its drawbacks, such as iron sludge formation and strict pH requirements, constrain its practical applications. To overcome these limitations, this study developed an iron-modified self-breathing electrode (Fe<sub>3</sub>O<sub>4</sub>/MGF<sub>if</sub>) through impregnation and filtration, characterized it, and applied it to construct a heterogeneous EF system for treating nanofiltration concentrates (NFCs). Under optimal conditions, the Fe<sub>3</sub>O<sub>4</sub>/MGF<sub>if</sub> electrode achieved COD and TOC removal efficiencies of 74.2 ± 1.8 % and 81.6 ± 1.7 %, respectively, within 2 h. Moreover, the modified electrode demonstrated degradation efficiency in the heterogeneous EF system comparable to that in the homogeneous EF system, while eliminating iron sludge formation and expanding the applicable pH range. Radical scavenging, quenching experiments and electron paramagnetic resonance (EPR) technique demonstrated that the electrode generated substantial ·OH and minor amounts of superoxide radicals (·O<sub>2</sub><sup>−</sup>) during NFCs degradation. The ultraviolet fluorescence spectra and three-dimensional fluorescence spectra indicated that reactive radicals efficiently degraded humic substances in NFCs, reduced aromatization, and significantly enhanced biochemical properties. This study resolves the challenges of iron sludge formation and pH constraints in homogeneous EF-based NFCs treatment and proposes a novel pathway capable of efficiently degrading recalcitrant organic pollutants by self-breathing.</div></div>","PeriodicalId":17528,"journal":{"name":"Journal of water process engineering","volume":"72 ","pages":"Article 107480"},"PeriodicalIF":6.3000,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of water process engineering","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2214714425005525","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
The homogeneous electro-Fenton(EF) technique is widely recognized in water treatment for its efficient generation of hydroxyl radicals (·OH). However, its drawbacks, such as iron sludge formation and strict pH requirements, constrain its practical applications. To overcome these limitations, this study developed an iron-modified self-breathing electrode (Fe3O4/MGFif) through impregnation and filtration, characterized it, and applied it to construct a heterogeneous EF system for treating nanofiltration concentrates (NFCs). Under optimal conditions, the Fe3O4/MGFif electrode achieved COD and TOC removal efficiencies of 74.2 ± 1.8 % and 81.6 ± 1.7 %, respectively, within 2 h. Moreover, the modified electrode demonstrated degradation efficiency in the heterogeneous EF system comparable to that in the homogeneous EF system, while eliminating iron sludge formation and expanding the applicable pH range. Radical scavenging, quenching experiments and electron paramagnetic resonance (EPR) technique demonstrated that the electrode generated substantial ·OH and minor amounts of superoxide radicals (·O2−) during NFCs degradation. The ultraviolet fluorescence spectra and three-dimensional fluorescence spectra indicated that reactive radicals efficiently degraded humic substances in NFCs, reduced aromatization, and significantly enhanced biochemical properties. This study resolves the challenges of iron sludge formation and pH constraints in homogeneous EF-based NFCs treatment and proposes a novel pathway capable of efficiently degrading recalcitrant organic pollutants by self-breathing.
期刊介绍:
The Journal of Water Process Engineering aims to publish refereed, high-quality research papers with significant novelty and impact in all areas of the engineering of water and wastewater processing . Papers on advanced and novel treatment processes and technologies are particularly welcome. The Journal considers papers in areas such as nanotechnology and biotechnology applications in water, novel oxidation and separation processes, membrane processes (except those for desalination) , catalytic processes for the removal of water contaminants, sustainable processes, water reuse and recycling, water use and wastewater minimization, integrated/hybrid technology, process modeling of water treatment and novel treatment processes. Submissions on the subject of adsorbents, including standard measurements of adsorption kinetics and equilibrium will only be considered if there is a genuine case for novelty and contribution, for example highly novel, sustainable adsorbents and their use: papers on activated carbon-type materials derived from natural matter, or surfactant-modified clays and related minerals, would not fulfil this criterion. The Journal particularly welcomes contributions involving environmentally, economically and socially sustainable technology for water treatment, including those which are energy-efficient, with minimal or no chemical consumption, and capable of water recycling and reuse that minimizes the direct disposal of wastewater to the aquatic environment. Papers that describe novel ideas for solving issues related to water quality and availability are also welcome, as are those that show the transfer of techniques from other disciplines. The Journal will consider papers dealing with processes for various water matrices including drinking water (except desalination), domestic, urban and industrial wastewaters, in addition to their residues. It is expected that the journal will be of particular relevance to chemical and process engineers working in the field. The Journal welcomes Full Text papers, Short Communications, State-of-the-Art Reviews and Letters to Editors and Case Studies