Enhanced power production of microbial fuel cells by reducing the oxygen and nitrogen functional groups of carbon cloth anode

The physicochemical properties of anode material are important for the electron transfer of anode bacteria and electricity generation of microbial fuel cells (MFCs). In this work, carbon cloth anode was pretreated with isopropanol, hydrogen peroxide (H2O2) and sodium hypochlorite (NaOCl) in order to reduce the anode functional groups. The influence of functional groups on the electrochemical properties of carbon cloth anode and power generation of MFCs was investigated. The anode pretreatments removed the surface sizing layer of carbon cloth and substantially reduced the contents of C-O and pyridinic/pyrrolic N groups on the anode. Electrochemical impedance spectroscopy and cyclic voltammetry analyses of the biofilm-matured anodes revealed an enhanced electrochemical electron transfer property because of the anode pretreatments. As compared with the untreated control (612 +/- 6mWm(-2)), the maximum power density of an acetate-fed single-chamber MFC was increased by 26% (773 +/- 5mWm(-2)) with the isopropanol treated anode. Additional treatment with H2O2 and NaOCl further increased the maximum power output to 844 +/- 5mWm(-2) and 831 +/- 4 mWm(-2). A nearly inverse liner relationship was observed between the contents of C-O and pyridinic/pyrrolic N groups on anodes and the anodic exchange current density and the power output of MFCs, indicating an adverse effect of these functional groups on the electricity production of anodes. Results from this study will further our understanding on the microbial interaction with carbon-based electrodes and provide an important guidance for the modification of anode materials for MFCs in future studies. Copyright (c) 2016 John Wiley & Sons, Ltd.