Improving the anodic packing and harmonizing the proton exchange membrane of bioelectrochemical systems for treating waste gases and generating electricity

Abstract

Conductive (carbonized porous ceramic ring, CPCR or Cp) and non-conductive filters (porous ceramic ring, PCR or P) were used as anode packing materials in a biotrickling filter microbial fuel cell (BTF-MFC). The optimal packing ratio (2:1 for CPCR: PCR, expressed as Cp2P1) yielded 1.1 times and 1.5 times higher rates of decomposition of acetone than did Cp1P2. Nano zero-valent iron (nZVI) in the proton exchange membrane (PEM) not only reduces the oxygen diffusion rate, but also improves the proton transfer capacity. The tensile strength of the PEM to which was added nZVI (5 mg ml−1) was 1.29 times higher than that of conductive carbon black (CCB) and polyvinyl alcohol (PVA) hydrogel (PVA/CCB-H) before drying and 1.23 times higher after drying. A combination of this composite material and BTF-MFC can be used to treat gaseous pollutants, increasing both removal efficiency and power generation. The microbial population could be increased by controlling the characteristics of the packing materials. On the non-conductive materials near the PEM, the dominant species of bacteria were aerobic, while on the conductive materials far from the PEM, more bacteria were anaerobic, so the filter materials could be distributed to improve the acetone removal capacity and power output of the BTF-MFC.