Enhanced methane producing microbial electrolysis cells for wastewater treatment using poly(neutral red) and chitosan modified electrodes

Microbial electrolysis cells (MECs) consisting of a bioanode and biocathode offer a promising solution for wastewater treatment. These systems can degrade organic substances at the bioanode while converting carbon dioxide (CO2), a major greenhouse gas, to a value-added fuel, methane (CH4) at the biocathode. The bioelectrodes were inoculated with a mixed culture under anaerobic conditions. By applying a constant potential of 0.40 V vs. Ag/AgCl (3 M NaCl), the long-term performance of MECs has been studied by monitoring the removal of chemical oxygen demand (COD) in the anolyte which contained synthetic wastewater and CH4 generation in the cathode chamber. To investigate the effect of electrode modification, poly(neutral red) and chitosan modified carbon felt electrodes were prepared, and applied in MECs. The results revealed that MECs with modified electrodes showed remarkably enhanced overall performance. The average COD removal efficiency, faradaic efficiency towards CO2 reduction to CH4 and CH4 production yield of modified MECs were up to 67%, 55% and 0.14 LCH4/gCOD, respectively.