Kotoka Francis, Merino-Garcia Ivan, Velizarov Svetlozar
Associated Laboratory for Green Chemistry-Clean Technologies and Processes (LAQV), REQUIMTE, Chemistry Department, FCT, Universidade Nova de Lisboa, Caparica 2829-516, Portugal.
Membranes (Basel). 2020 Jul 22;10(8):160. doi: 10.3390/membranes10080160.
Reverse electrodialysis (RED) technology represents a promising electro-membrane process for renewable energy harvesting from aqueous streams with different salinity. However, the performance of the key components of the system, that is, the ion exchange membranes, is limited by both the presence of multivalent ions and fouling phenomena, thus leading to a reduced generated net power density. In this context, the behavior of anion exchange membranes (AEMs) in RED systems is more severely affected, due to the undesirable interactions between their positively charged fixed groups and, mostly negatively charged, foulant materials present in natural streams. Therefore, controlling both the monovalent anion permselectivity and the membrane surface hydrophilicity is crucial. In this respect, different surface modification procedures were considered in the literature, to enhance the above-mentioned properties. This review reports and discusses the currently available approaches for surface modifications of AEMs, such as graft polymerization, dip coating, and layer-by-layer, among others, mainly focusing on preparing monovalent permselective AEMs with antifouling characteristics, but also considering hydrophilicity aspects and identifying the most promising modifying agents to be utilized. Thus, the present study aimed at providing new insights for the further design and development of selective, durable, and cost-effective modified AEMs for an enhanced RED process performance, which is indispensable for a practical implementation of this electro-membrane technology at an industrial scale.
反向电渗析（RED）技术是一种很有前景的电膜工艺，可从不同盐度的水流中获取可再生能源。然而，该系统关键组件即离子交换膜的性能受到多价离子的存在和污垢现象的限制，从而导致产生的净功率密度降低。在这种情况下，由于阴离子交换膜（AEM）带正电荷的固定基团与天然水流中大多带负电荷的污垢物质之间存在不良相互作用，其在RED系统中的性能受到的影响更为严重。因此，控制单价阴离子选择透过性和膜表面亲水性至关重要。在这方面，文献中考虑了不同的表面改性方法来增强上述性能。本综述报告并讨论了目前用于AEM表面改性的方法，如接枝聚合、浸涂和层层组装等，主要侧重于制备具有抗污染特性的单价选择透过性AEM，同时也考虑亲水性方面并确定最有前景的改性剂。因此，本研究旨在为进一步设计和开发选择性、耐用且经济高效的改性AEM提供新的见解以提高RED工艺性能，这对于该电膜技术在工业规模上的实际应用不可或缺。
