Simultaneous Removal of Toluene in Gas and Electricity Production by Using a Single-Chamber Microbial Fuel Cell-Biotricking Filter System

Biotrickling filters (BTFs) combined with microbial fuel cell (MFC) provide a sustainable approach to remove volatile organic compounds accompanied by electricity production. In this study, an integrate system (SMFC-BTF) combining single-chamber MFC with BTF is constructed and used to remove toluene-containing gas. A stable removal efficiency of ∼80% is obtained for the 800 ppm toluene accompanied with the current output of 0.25 mA, indicating the feasibility of SMFC-BTF for the simultaneous removal of toluene and electricity production. Moreover, the removal efficiency increases to 95% when the inlet toluene concentration is below 400 ppm under the empty bed retention time of 180s. The detection of intermediate products reveals that cresol, benzyl alcohol, hydroxybenzoic acid, and dihydroxybenzoic acid are produced during the oxidation of toluene by aerobic and anaerobic microorganisms. Accordingly, the pathways of toluene degradation in SMFC-BTF are proposed. The significant difference of microbial species growing in different parts of SMFC-BTF suggests that the process of toluene removal in the system is spatial difference. Our results provide a promising system for the simultaneous removal of toluene and energy recovery.