Doped polymethyl methacrylate (PMMA) as proton exchange membrane for microbial fuel cell

Abstract The urgent need for clean and affordable energy solutions to combat energy scarcity and global warming is paramount. Fuel cells, particularly microbial fuel cells (MFCs), offer a promising avenue for sustainable energy production. Proton exchange membranes (PEMs) are critical components in MFCs, but the high cost of Nafion, the gold standard PEM, poses a significant challenge. In this pioneering study, we tried to fabricate PEMs by crafting them from polymethyl methacrylate (PMMA), coupled with innovative combinations of potassium thiocyanate (KSCN) and citric acid. The synthesized membranes were studied for their water uptake capacity, ion exchange capacity and potential applications in MFC. The maximum remarkable water uptake capacities of up to 70 % for 10 % KSCN and 64 % for 7.5 % citric acid compositions was observed. Furthermore, these PEMs exhibit ion exchange capacities (IEC) ranging from 0.024 to an impressive 0.69 meq/gm, with the 7.5 % citric acid variant showcasing the highest IEC (0.69 meq/gm). The membranes having better IEC were applied to microbial fuel cell. This results in maximum power density of 50.03 μw/cm 2 , underscoring the tremendous potential these membranes hold as a cost-effective and environmentally friendly alternative to conventional PEMs in MFCs.