Sustainable and continuous removal of trimethylamine in a bio‐photoelectrochemical reactor using g‐C₃N₄/TiO₂ photocathode with power generation

Abstract

BACKGROUND: Trimethylamine (TMA), as a harmful nitrogenous gas, is potentially toxic to animals and human beings. In recent years, the emission of TMA has caused huge environmental problems. TMA is strongly toxic and carcinogenic and requires efficient treatment technology. Photocatalysis and photoelectrocatalysis (PEC) have attracted great interest because of their environmental friendliness and high efficiency. The key problem is how to construct high-efficiency systems and prepare high-activity catalysts.RESULTS: To eradicate TMA in air, an efficient electrochemical system with bio-anode and photocathode (g-C 3 N 4 -TiO 2 ) was designed. It removed TMA in air continuously and efficiently, for both single-cathode and double-cathode systems. This is the first report about TMA removal in such integrated g-C 3 N 4 /TiO 2 photocathode and bio-electrochemical system. Effects of reaction conditions were investigated, such as the TMA concentrations and flow rates. The highest efficiency for TMA removal was in an integrated PEC and microbial fuel cell (MFC) system with potassium persulfate (PS) activation. The double-cathode PEC-MFC-PS system could remove more TMA (1.9 g m −3 h −1 versus 1.3 g m −3 h −1 ) compared with the double-cathode PEC-MFC system. CONCLUSIONS: A novel TMA treatment system -PEC-MFC systemwas constructed, coupling PEC with MFC for continuous removal of TMA from air. Combined with activated PS, a PEC-MFC-PS system was designed and constructed and proved effective in oxidizing gaseous TMA and generating electricity at the same time, which has practical application prospects for the treatment of TMA pollution.