Role of anion exchange membrane fouling in reverse electrodialysis using natural feed waters

Publication date: Available online 9 October 2018Source: Colloids and Surfaces A: Physicochemical and Engineering AspectsAuthor(s): T. Rijnaarts, J. Moreno, M. Saakes, W.M. de Vos, K. NijmeijerAbstractReverse electrodialysis (RED) is a process to harvest renewable energy from salinity gradients. Under lab conditions with artificial salt solutions, promising results have been achieved in recent years. However, in large scale industrial applications, natural waters are used and that poses challenges such as fouling. Fouling of anion exchange membranes (AEMs) by organic matter (e.g. humic acids) has been identified as a possible cause that lowers RED performance with natural waters. In this work, natural river and seawater at the Afsluitdijk (The Netherlands) are used to study the RED performance of six different AEMs. These AEMs are characterized before and after RED experiments with natural waters. The effect of natural fouling is found to be specific for each AEM and highly dependent on their respective chemistries and associated membrane properties. Firstly, aromatic AEMs with a low swelling degree showed a permselectivity decrease as well as membrane resistance increase. Secondly, aliphatic AEMs with a medium swelling degree experienced only a membrane resistance increase. Finally, only a decrease in permselectivity was observed for aliphatic AEMs with large swelling degrees. Subsequently, the effect of AEM fouling is compared to the observed decrease in RED performance and...
Source: Colloids and Surfaces A: Physicochemical and Engineering Aspects - Category: Chemistry Source Type: research