A study on development of alternative biopolymers based proton exchange membrane for microbial fuel cells and effect of blending ratio and ionic crosslinking on bioenergy generation and COD removal

The use of biopolymers as alternative proton exchange membranes (PEMs) is receiving significant attention in microbial fuel cells (MFCs) due to their attractive and competitive physico-chemical properties, eco-friendly behavior and biodegradable nature. In this study we developed the biopolymer-based blend PEMs using chitosan (Cs) alginate (Alg) for bioelectricity production and simultaneous wastewater treatment and also investigated the effect of blending ratio of the membrane and ionic crosslinking between the two biopolymers on MFC performance. The membranes of Cs:Alg were fabricated in volume ratio of 100:0, 80:20, 60:40, 50:50, 40:60, 20:80, and 0:100 via a solution casting and solvent evaporation method followed by crosslinking with phosphoric acid to avoid excess swelling of the hydrophilic polymers and increase the mechanical strength. Among these, the 50:50 ratio membranes exhibited the highest power generation (115 mW/m 2 ) with 1340% water uptake, however the membrane with 40:60 ratio displayed maximum COD removal (78.6%) compared to other membranes. The structure and surface morphology of obtained membranes were examined using Infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX), Sorption and cation exchange capacity, and tensile strength. Sorption, cation exchange capacity and mechanical properties of Cs membranes increased with the addition of Alg with near to stoichiometric ratio.