Four-in-one multifunctional self-driven photoelectrocatalytic system for water purification: Organics degradation, U(VI) reduction, electricity generation and disinfection against bacteria

This study addresses the energy-intensive nature of conventional wastewater treatment processes and proposes a solution through the development of a green, low-energy, and multifunctional wastewater treatment technology. The research focuses on a multifunctional self-driven photoelectrocatalytic (PEC) system, exploring its four-in-one applications in eliminating organic pollutants, reducing U(VI), generating electrical energy, and disinfecting pathogenic microorganisms. A TiO2-decorated carbon felt (CF@TiO2) cathode is synthesized to enhance interfacial charge transfer, with TiO2 coating improving surface binding sites (edge TiO and adsorbed -OH) for UO22+ adsorption and reduction. The self-driven PEC system, illuminated solely with simulated sunlight, exhibits remarkable efficiency in removing nearly 100 % of uranium within 0.5 h and simultaneously degrading 99.9 % of sulfamethoxazole (SMX) within 1.5 h, all while generating a maximum power output density (Pmax) of approximately 1065 μW·cm−2. The system demonstrates significant anti-interference properties across a wide pH range and coexisting ions. Moreover, 49.4 % of the fixed uranium on the cathode is reduced into U(IV) species, limiting its migration. The self-driven PEC system also excels in detoxifying various toxic organic compounds, including tetracycline, chlortetracycline, and oxytetracycline, and exhibits exceptional sterilization ability by disinfecting nearly 100 % of Escherichia coli within 0.5 h. This work presents an energy-saving, sustainable, and easily recyclable wastewater purification system with four-in-one capabilities, relying solely on sunlight for operation. This work developed a self-driven photoelectrocatalytic system, composing of a TiO2 nanorod array photoanode, silicon cell and TiO2 coated carbon fibre cathode, and demonstrated its four-in-one applications in organic matter degradation, uranium reduction, sterilization and electrical energy generation using only sunlight. [Display omitted] •A self-driven PEC system is developed by a TNR photoanode, SC and CF@TiO2 cathode.•CF@TiO2 enhances the system's pollutant removal and energy output compared to CF.•The system shows excellent activities in removing SMX and UO22+ and power output.•Exceptional sterilization ability by disinfecting ∼100 % of E•coli within 0.5 h is achieved.•The system also shows high efficacy in detoxification of toxic organic pollutants.