Novel composite polybenzimidazole-based proton exchange membranes as efficient and sustainable separators for microbial fuel cells

Microbial fuel cells (MFCs) are gaining increasing technological relevance for wastewater remediation and ancillary energy production. MFC separators are often fabricated with ion-exchange perfluorinated membranes, the most common of them being Nafion™. Here, we prepared composite separators based on polybenzimidazole (PBI), where the filler is made of SBA-15 mesostructured silica functionalized with sulphonic moieties. These membranes allowed strong increase of power density (up to one order of magnitude), operating life and wastewater treatment efficiency with respect to Nafion™. Moreover, our sustainability and cost analysis clearly showed that PBI is more convenient than Nafion™ for making these membranes. Therefore, we conclude that PBI-based membranes are very promising as separators for MFCs.