Greywater and bacteria removal with synchronized energy production in photocatalytic fuel cell based on anodic TiO2/ZnO/Zn and cathodic CuO/Cu

An approach that can recuperate of energy from wastewater treatment process is highly necessitate and would help to surmount the both environmental pollution and energy crisis issues. A photocatalytic fuel cell (PFC) employing an anodic TiO2/ZnO/Zn and a cathodic CuO/Cu has been applied to degrade the raw greywater, which realized advanced organics destruction, bacteria disinfection, and synchronously electricity production. The improved photocatalytic performance has been observed when the cell was incorporated with anodic TiO2/ZnO/Zn under UV and sunlight irradiation due to the enhanced electric field conductivity of the catalysts and heterojunction interface of TiO2. In the constructed UV-activated PFC system, the electricity production capability was observed with the measured voltage and power density of 868 mV and 0.0172 mW cm−2, respectively. Advanced chemical oxygen demand (COD) removal efficiency of greywater achieved a 100% completion within 60 min of light irradiation. The Escherichia coli (E. coli) colonies decreased significantly and accounted ∼99% disinfection efficiency. Moreover, the photoelectrochemical and photoluminescence (PL) experiments elucidated that the charge carrier separation efficiency were higher when TiO2 was coupled to ZnO. The organic matter elimination principle was assessed by radical trapping experiment, and the findings indicated that the hydroxyl (OH) radical and hole (h+) appeared as major functions in the reaction. The stable cycle operation of the cell has been also obtained owing to the stable and film-type materials of anodic material. This performance was among the highest documented for PFC using real wastewater effluent as the fuel source. [Display omitted] •Anodic TiO2/ZnO/Zn and cathodic CuO/Cu was integrated in a PFC.•The PFC was assembled to recover energy from greywater and bacteria disinfection.•Electricity output is promoted by TiO2 as a charge separator on ZnO/Zn alone.•Greywater was totally mineralized and ∼99% bacteria disinfection can be achieved.•The stable cycle operation of the cell has been also obtained.