Development of microbial chondroitin sulfate-based proton exchange membranes for microbial fuel cells

Technological developments have led to a significant increase in energy demand, and thus the interest in alternative energy has increased in the same direction. For this reason, fossil fuel reserves and climate-based renewable energy sources were used as alternatives in energy production, but the desired success was not fully achieved due to the decrease in fossil fuel and climate changes, and a new alternative energy source was sought. This situation has made Microbial Fuel Cells (MFC), which can directly convert chemical energy, an important alternative to renewable energy, from organic waste into electrical energy with the help of microorganisms. Therefore, in this study, microbially obtainable chondroitin, which is a non-toxic, biocompatible organic molecule that will not disrupt the ecological balance, sulfate-based proton exchange membrane was prepared for the microbial fuel cell. For this, Chondroitin was synthesized by the microbial method, chondroitin sulfate was obtained by sulfation, and chondroitin sulfate membranes were prepared by cross-linking with sulfosuccinic acid at varying molar concentrations (0.2, 0.4, 0.6, and 0.8). Firstly, the structural characterization, thermal properties, and morphological features of the prepared 20 mm thickness membranes were investigated, and then the effects of parameters such as pH change, voltage, quaternization, internal resistance, and coulomb efficiency on microbial fuel cell performance were studied. The best result was found to be that of chondroitin sulfate cross-linked with 0.8 M sulfosuccinic acid, which had an internal resistance of 0.310 Ω, a power density of 30 mW/m2, and a coulomb efficiency of 70 %. Additionally, proton conductivity was measured to be 0.9919 mS/cm, and thanks to the proton conduction efficiency of the designed Microbial chondroitin sulfate membranes, it has been determined that it has an effective proton exchange membrane potential. These developments show that microbial chondroitin sulfate-based membranes may be an alternative candidate for microbial fuel cells.