Kinetic analysis of electron transfer process in decolorization of azo dyes by Shewanella combined with porous organic polymers in MFCs

Abstract

Two-dimensional nanostructured materials have emerged as very promising electrode materials for bioelectrochemical systems, enabling high bioelectrical output. We constructed air-cathode microbial fuel cells (MFCs) with electrical energy storage material POPM-TFP-rGO modified anodes for methyl orange (MO) decolorization and investigated the MFC performance. The kinetics of these processes were further analyzed. The results showed that MO decolorization efficiency in the POPM-TFP-rGO material-modified anode MFC reached 69.5% at 10 h. Compared with the unmodified electrode MFC, the efficiency and the kinetic constant of MO decolorization increased by 26.4% and 219%, respectively. Compared with control (40.5 mA m-2, 4.16 mW m-2), the stable current density and maximum power density (162.5 mA m-2, 48.84 mW m-2) were enhanced by 301% and 1070%, respectively. Further analysis of extracellular electron transfer kinetics showed that after modification of POPM-TFP-rGO, the number of electrons n and the charge transfer coefficient α (4, 0.56) increased by 74% and 65%, respectively, compared with control (2.3, 0.34). Therefore, POPM-TFP-rGO could be considered as a suitable and effective option for azo dye wastewater treatment by MFCs.