Low power production and unstable power supply are important bottlenecks restricting the application of microbial fuel cells (MFCs). It is necessary to explore effective methods to improve MFC performance. By using molasses wastewater as fuel, carbon felt as an electrode, and the mixture of K3[Fe(CN)6] and NaCl as a catholyte, an MFC experimental system was set up to study the performance of MFCs with three different proton exchange membranes. A Nafion membrane was used as the basic material, and polyvinylidene fluoride (PVDF) and acetone-modified PVDF were used to modify it, respectively. The experimental results show that a PVDF-modified membrane can improve the water absorption effectively and, thus, make the MFC have greater power generation and better wastewater treatment effect. The acetone-modified PVDF can further improve the stability of output power of the MFC. When the acetone-modified PVDF was used to modify the Nafion membrane, the steady output voltage of the MFC was above 0.21 V, and the Chemical Oxygen Demand (COD) removal rate for molasses wastewater was about 66.7%, which were 96.3% and 75.1% higher than that of the MFC with the ordinary Nafion membrane. Membrane modification with acetone-modified PVDF can not only increase the output voltage of the MFC but also improve the stability of its output electrical energy.

Proton exchange membrane is an important factor affecting the power generation capacity and water purification effect of microbial fuel cells. The performance of microbial fuel cells can be improved by modifying the proton exchange membrane by some suitable method. Microbial fuel cells with membranes modified by SiO2/PVDF (polyvinylidene difluoride), sulfonated PVDF and polymerized MMA (methyl methacrylate) electrolyte were tested and their power generation capacity and water purification effect were compared. The experimental results show that the three membrane modification methods can improve the power generation capacity and water purification effect of microbial fuel cells to some extent. Among them, the microbial fuel cell with the polymerized MMA modified membrane showed the best performance, in which the output voltage was 39.52 mV, and the electricity production current density was 18.82 mA/m2, which was 2224% higher than that of microbial fuel cell with the conventional Nafion membrane; and the COD (chemical oxygen demand) removal rate was 54.8%, which was 72.9% higher than that of microbial fuel cell with the conventional Nafion membrane. Modifying the membrane with the polymerized MMA is a very effective way to improve the performance of microbial fuel cells.