Destruction of tetracycline hydrochloride antibiotics by FeOOH/TiO2 granular activated carbon as expanded cathode in low-cost MBR/MFC coupled system

In this study, membrane bioreactor (MBR) and microbial fuel cell (MFC) was coupled for wastewater treatment using a polyvinylidene fluoride (PVDF) coated carbon fiber cloth as cathode membrane. To generate more power and mitigate membrane fouling, granular activated carbon (GAC) was added as a dynamic layer on cathode membrane. With or without FeOOH/TiO2 doping on GAC, 2e− or 4e− oxygen reduction reactions (ORRs) took place. The maximum power density reached 5.1 W m−3 via 4e− ORR, practically the highest compared to similar MBR/MFC coupled systems. The removal of COD and NH4+-N was 90% and 80%, respectively. With FeOOH/TiO2/GAC, hydrogen peroxide (H2O2) was formed via 2e− ORR, at 0.13 mg L−1 in effluent. Oxidative removal of a model pollutant tetracycline hydrochloride was 90% by reactive oxidizing species such as
- OH. This is the first report of H2O2 synthesis using doped GAC as expanded cathode in coupled bio-electrochemical MBR/MFC system. Compared to other electrochemical systems, our bio-electrochemical system was more energy-saving and environmental-friendly in wastewater treatment.