Department of Chemical Engineering, University of São Paulo (USP), Av. Professor Lineu Prestes, 580, Bloco 18 - Conjunto das Químicas, 05434-070 São Paulo, Brazil; IEC Group, ISIRYM, Universitat Politècnica de València, Camí de Vera s/n, 46022, P.O. Box 22012, València E-46071, Spain.
IEC Group, ISIRYM, Universitat Politècnica de València, Camí de Vera s/n, 46022, P.O. Box 22012, València E-46071, Spain.
Adv Colloid Interface Sci. 2021 Jul;293:102439. doi: 10.1016/j.cis.2021.102439. Epub 2021 May 10.
Electrodialysis is mostly used for drinking water production but it has gained applicability in different new fields in recent decades. Membrane characteristics and ion transport properties strongly influence the efficiency of electrodialysis and must be evaluated to avoid an intense energy consumption and ensure long membrane times of usage. To this aim, conducting studies on ion transport across membranes is essential. Several dynamic characterization methods can be employed, among which, chronopotentiometry has shown special relevance because it allows a direct access to the contribution of the potential in different states of the membrane/solution system. The present paper provides a critical review on the use of chronopotentiometry to determine the main membrane transport properties and to evaluate mass transfer phenomena. Properties, such as limiting current density, electrical resistances, plateau length, transport number of counter-ions in the membrane, transition times, and apparent fraction of membrane conductive area have been intensively discussed in the literature and are presented in this review. Some of the phenomena evaluated using this technique are concentration polarization, gravitational convection, electroconvection, water dissociation, and fouling/scaling, all of them also shown herein. Mathematical and experimental studies were considered. New trends in chronopotentiometric studies should include ion-exchange membranes that have been recently developed (presenting anti-fouling, anti-microbial, and monovalent-selective properties) and a deeper discussion on the behaviour of complex solutions that have been often treated by electrodialysis, such as municipal wastewaters. New mathematical models, especially 3D ones, are also expected to be developed in the coming years.
电渗析主要用于饮用水生产，但在最近几十年中，它在不同的新领域得到了应用。膜特性和离子传输特性强烈影响电渗析的效率，必须进行评估，以避免能源消耗过大，并确保膜的使用寿命长。为此，研究离子在膜中的传输至关重要。可以采用几种动态特性研究方法，其中，计时电位法具有特殊的重要性，因为它可以直接了解膜/溶液系统不同状态下的电位贡献。本文对计时电位法在确定主要膜传输特性和评估传质现象中的应用进行了批判性回顾。文献中对极限电流密度、电阻、平台长度、膜中反离子的迁移数、过渡时间和膜导电面积的表观分数等特性进行了深入讨论，并在本综述中进行了介绍。使用该技术评估的一些现象包括浓差极化、重力对流、电对流、水离解和结垢/结垢，所有这些现象也在本文中进行了展示。考虑了数学和实验研究。计时电位研究的新趋势应包括最近开发的离子交换膜（具有抗污染、抗微生物和单价选择性特性），并深入讨论电渗析经常处理的复杂溶液的行为，例如城市废水。预计未来几年还将开发新的数学模型，特别是 3D 模型。
