Integrated approach to uranium recovery and organic decomposition with electricity generation in a self-driven photoelectrochemical system

Abstract

Simultaneous uranium recovery, organic pollutant degradation, and electricity generation were achieved by employing a self-driven photoelectrochemical (PEC) system equipped with a modified carbon felt (MCF) cathode for the treatment of complex radioactive wastewater. The MCF cathode was synthesized via a facile hydrothermal method, which modified the surface functional groups on carbon felt (CF) with enhanced active site availability and facilitated interfacial charge transfer, thus improving its UO₂²⁺ adsorption and reduction capacities. The self-driven PEC system with the MCF cathode demonstrated remarkable removal efficiencies and rate constants (k) for UO₂²⁺ (98.8 % and 0.111 min⁻¹) and chlortetracycline hydrochloride (CTC) (92.9 % and 0.028 min⁻¹) within 40 min and 90 min, respectively, coupled with an excellent power output of 1.41 mW/cm². Additionally, the system with the MCF cathode exhibited superior removal performance for UO₂²⁺ and CTC in treating model complex wastewater under wide conditions. Even under natural sunlight, the system achieved over 80 % removal efficiency for both UO₂²⁺ and CTC. Moreover, the uranium immobilized on the MCF cathode was mainly reduced to U(IV) species (90.51 %), and performance remained robust over ten operational cycles. The cathode surface modification strategy and its application in the system provide a cost-effective, multi-functional and high-efficiency approach to controlling nuclides and organic pollutants in complex radioactive wastewater.