Efficient photocatalysis combined with microbial catalysis for synergistical degradation of antibiotic in a bioelectrochemical system

In this study, a self-driven bioelectrochemical system (PMBES) consisting of a photocatalyst-microorganism coupled anode and a chemical cathode was constructed, enabling highly efficient degradation of sulfamethoxazole (SMX). Reduced graphene oxide modified carbon felt was used as the anode substrate, which was further loaded with oxygen vacancy-engineered BiVO₄ and hydrophobically modified using DTMS. A carbon brush in a potassium ferricyanide solution was adopted as the cathode. Under an incident luminous flux of 100 lm and an initial SMX concentration of 5 mg/L, the PMBES achieved an SMX degradation efficiency of 73.4% and a maximum power density of 912.6 mW/m², representing respective improvements of 20.53% and 70% relative to the photocatalyst-free control system. This PMBES efficiently integrates green solar energy with the chemical energy inherent in SMX-containing wastewater. The underlying mechanism is that photogenerated charge carriers from the photocatalytic process accelerate the extracellular electron transfer of the electroactive microorganism, thus boosting the system's electricity generation. Meanwhile, the spontaneous electric field produced by electroactive microorganisms promotes the separation of photogenerated electron-hole pairs in oxygen vacancy-engineered BiVO₄, ultimately realizing the synergistic degradation of SMX. This work provides an innovative and energy-efficient strategy for the treatment of refractory antibiotic wastewater.