Optimization of the microbial fuel cells operation for wastewater treatment by using cylindrical ceramic membranes

The present investigation focuses on the design and construction of microbial fuel cells (MFCs) using cylindrical composite membranes in the vertical position, in order to treat domestic wastewater and generate electricity. The composite membranes were prepared with natural clay and activated carbon modified with chlorosulfonic acid using a physical mixture of 85 % clay and 15% modified carbon, and they received a heat treatment at 1000 degrees C to improve their mechanical resistance. Also, the physicochemical characterization of the composite membranes and their precursors was carried out to determine their morphology, functionalities, and chemical composition. In addition, ion transport tests across membranes were performed to evaluate their ion exchange properties. The components of the MFCs include a polypropylene vessel as the anode chamber, a graphite filter as the anode collector, a stainless-steel mesh as the cathode collector, and a cylindrical membrane as the ion exchange material. Different configurations were tested based on the cathode-anode size proportion (1:1, 1:2, and 2:1). The MFCs were operated at room temperature using wastewater from a municipal treatment plant with sodium acetate as a substrate. The stability and durability of the MFCs were evaluated by monitoring the voltage and power density over time. The composition of the wastewater was analyzed before and after each operation cycle. In general, composite membranes of clay and bituminous carbon modified with chlorosulfonic acid showed favorable characteristics for MFCs applications, such as better ion transport and conductivity. Cells using these membranes with a 2 cm electrode spacing and a cathode: anode size proportion of 1:2 demonstrated the best performance in terms of electricity generation and wastewater treatment. These MFCs achieved a power density of 24.76 mW/m3 and successfully powered an LED and digital clock as prototypes and reduced the overall Chemical Oxygen Demand (COD) by 77.96 %.