Crucial roles of aeration and catalyst on caffeine removal and bioelectricity generation in a double chambered microbial fuel cell integrated electrocatalytic process

The effects of aeration and catalyst on caffeine removal in the cathodic chamber and electricity generation of a double chambered microbial fuel cell (MFC) integrated electrocatalytic process were investigated. The overall performances of MFC in caffeine removal and electricity generation were significantly enhanced under the presence of copper (II) oxide (CuO) and aeration. CuO was synthesized using a hydrothermal method and was immobilized on the carbon plate for application as cathode. The CuO particles and CuO loaded carbon plate (CuO/C) were characterized by using X-ray diffractometer and scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy. The effective transfer of electrons from anodic chamber to cathodic chamber for oxygen reduction reaction (ORR) accelerated the removal of caffeine using CuO/C cathode under aerated condition. Results revealed that 15-fold higher removal efficiency of caffeine was obtained using CuO/C cathode (52.16 %) as compared with that of bare carbon plate (bare C) (3.41 %) at the first 24 h under aerated condition. The highest maximum power density and current density (28.75 mW m-2 and 253.33 mA m-2) were obtained for CuO/C cathode under aerated condition. Bare C cathode possessed the lowest maximum power density and current density (9.75 mW m-2 and 106.67 mA m-2) under unaerated condition. The circuit connection greatly improved the chemical oxygen demand removal of synthetic wastewater in the anodic chamber when the cathodic chamber was under aerated condition. The detailed mechanisms of the effects of CuO catalyst and aeration on the ORR at cathodic chamber were discussed.