Mass transfer and multi-phase fluid flow in electro-coagulation: A review

IF 11.4 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Water Research Pub Date : 2025-04-25 DOI:10.1016/j.watres.2025.123715

Yanqing Fang, Yan Huang, Xingyu He, Hailing Liu, Yasir Ullah, Hazrat Bilal, Jun Lu

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引用次数: 0

Abstract

In electrocoagulation (EC), the electro-generated coagulants Fe²⁺ (or Al³⁺) and OH⁻ transfer into the bulk solution and undergo spontaneous hydrolysis reactions to form flocs which can absorb various pollutants through surface adsorption, complexation reaction and ligand exchange. This work presents a review on recent literatures about the multi-phase fluid flow (the transport of bubbles and flocs phase) and the mass transfer of electro-generated species (coagulants, OH⁻, dissolved oxygen, etc.), as well as their impact on flocs generation, pollutant removal and energy consumption. The coupled relationship among the electric field, the mass transfer and the multi-phase fluid flow could be studied by the modeling methods. The simplified model without considering mass transfer could be applied to describe the current and electric field characteristics. The model considering mass transfer and fluid flow could solve the coupled relationship among electric field, concentration field and flow field. The continuous wastewater phase forms a multi-phase flow with the subsequent generation of bubble and floc phases. The multi-phase fluid flow is proven to have a crucial effect on EC performance. This work also reviews the effect of mass transfer of electro-generated coagulants and OH⁻ on flocs generation and clarifies that it is not the initial value but the local pH or pH profiles has a more important impact on the floc generation and pollutant removal. This review provides insight into multi-phase fluid flow and mass transfer in EC, delivers guidelines for sustaining high treatment performance, and offers an outlook for the future development of EC.

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电凝过程中的传质和多相流体流动：综述

在电混凝（EC）中，电生成的混凝剂Fe2+（或Al3+）和OH−转移到体溶液中，通过表面吸附、络合反应和配体交换形成絮凝体，吸附各种污染物。本文综述了近年来关于多相流体流动（气泡和絮凝体相的传输）和电生成物质（混凝剂、OH−、溶解氧等）的传质及其对絮凝体生成、污染物去除和能耗的影响的研究进展。利用该模型可以研究电场、传质和多相流体流动之间的耦合关系。不考虑传质的简化模型可以用来描述电流和电场特性。考虑传质和流体流动的模型可以解决电场、浓度场和流场之间的耦合关系。连续的废水相形成多相流，随后产生气泡相和絮体相。多相流体流动对EC的性能有重要影响。本文还回顾了电致混凝剂和OH -传质对絮凝体产生的影响，并阐明了对絮凝体产生和污染物去除更重要的不是初始值，而是局部pH或pH值。本文综述了EC中多相流体的流动和传质过程，为维持EC的高处理性能提供了指导，并对EC的未来发展进行了展望。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Water Research 环境科学-工程：环境

CiteScore

20.80

自引率

9.40%

发文量

1307

审稿时长

38 days

期刊介绍： Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include: •Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management; •Urban hydrology including sewer systems, stormwater management, and green infrastructure; •Drinking water treatment and distribution; •Potable and non-potable water reuse; •Sanitation, public health, and risk assessment; •Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions; •Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment; •Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution; •Environmental restoration, linked to surface water, groundwater and groundwater remediation; •Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts; •Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle; •Socio-economic, policy, and regulations studies.