Biomass derived activated carbon cathode performance for sustainable power generation from Microbial Fuel Cells

Significant amount of wastewater is generated from Sewage, and treating this wastewater consumes huge amount of energy. Microbial Fuel Cells can be used to treat this wastewater and generate electricity in the process. Traditionally, Platinum catalyst on Carbon Cloth is used as the cathode for oxygen reduction. In this work, an advanced cathode material in the form of an activated carbon derived from biomass sources was evaluated in terms of cathode performance, stability of operation and cost. For activated carbon cathode, an open circuit voltage of 580 ± 30 mV was achieved between fed-batch cycles. Constant external load produced a peak current density and power density of 0.40 mA/m2 and 110 ± 6.58 mW/m2 respectively. Further polarization curves reveal system stability with varying resistances with a change in COD for the wastewater from 780 ± 20 mg/l to 260 ± 30 mg/l over two weeks of operation, achieving a removal efficiency of around 64%, the BOD content of the wastewater also reduced from 520 ± 20 mg/l to 165 ± 25 mg/l with a dissolved solutes removal efficiency of 51% during time of operation. Activated carbon derived from biomass sources is a promising alternative to expensive platinum; further it has a low surface pH, lacks any acidic surface functional group, and can be regenerated to more than 85% of its initial performance with dilute acid wash as compared to platinum which cannot be reused once fouled, thus implicating a sustainable solution.