Primary insights into the effects of organic pollutants and carbon-based cathode materials in a double chambered microbial fuel cell integrated electrocatalytic process

Cathode plays an important role on the oxygen reduction reaction (ORR) reactivity in the microbial fuel cell integrated electrocatalytic process for the effective degradation of organic pollutants. Comparative study of caffeine and phenol as the organic pollutants in the cathodic chamber was investigated in terms of removal efficiency and bioelectricity generation. Results revealed that the highest removal efficiency of phenol (96.89 ± 1.26%) and maximum power density (33.37 ± 4.62 mW m⁻²) were attained by copper (II) oxide loaded carbon felt (CuO/CF) cathode. Besides, the removal efficiency of phenol was nearly 12-fold higher (24.85 ± 1.36%) using CuO/CF cathode compared with that of caffeine (2.14 ± 0.36%) at the first 24 h. The effect of carbon-based cathode materials on the mineralization of caffeine in the cathodic chamber was evaluated using carbon felt (CF) and carbon plate (CP). Both CuO/CP and bare CP cathodes surpassed CuO/CF and bare CF cathodes in the chemical oxygen demand (COD) removal and bioelectricity generation. Higher crystallinity nature and electrical conductivity (3.57 × 10⁵ Ω⁻¹ m⁻¹) of CP compared with that of amorphous structure and lower electrical conductivity of bare CF (3.33 × 10⁴ Ω⁻¹ m⁻¹) contributed to higher ORR reactivity and efficient transport of electrons for bioelectricity generation. The COD removal efficiency of synthetic wastewater in the anodic chamber and bioelectricity generation of this integrated system were affected by the types of organic pollutants and carbon-based cathode materials in the cathodic chamber.