The application of radiation-grafted ion-exchange membranes in microbial fuel cells.

This project will look at the application and development of radiation-grafted ion-exchange membranes in a microbial fuel cells. An aim is to develop low resistance ion-exchange membranes (IEMs) that do not have increased O2 crossover. It has previously been found that the use of anion exchange membranes (AEMs) may improve the performance of microbial fuel cells. The literature suggests that the use of AEMs over cation-exchange membranes (CEMs) might give a more favourable power output. However, the radiation grafted (RG) AEMs tested in this study displayed a poorer performance both in situ and ex situ than the industry standard CEM (Nafion® 115). Lower MFC power density (ca. 8 mW m-2 for the RG-AEM compared to ca 10 mW m-2 for Nafion® 115) and lower conductivity (0.007 S cm-2 compared to 0.032 S cm-2) were both observed. An RG-CEM with the same base polymer as a previously tested RG-AEM was also produced. Comparisons between the MFC performance of the RG-CEM and Nafion® were more favourable, showing higher voltage output and lower O2 permeability. The results of an oxygen permeability test suggest that both the RG-AEMs and RG-CEMs exhibit a lower oxygen crossover, which is preferable when looking at MFC applications. However, the RG-AEM conductivities were lower than the RG-CEM and Nafion®. Despite this, the conductivities of the RG-AEMs were less affected when in contact with solutions containing buffer and bacteria. A recommendation for future work is to explore more widely the use of RG-CEM in MFCs