Chlorophenols Degradation And Inductive Effects On Biocathode Microbial Fuel Cells

Microbial fuel cells (MFCs) extracting energy from wastes or powering remote devices from sediments have attracted considerable research and public attention during the past decade. Microbial-cathode MFCs, or cathodes using only bacterial catalysts (biocathodes, BC), integrated three important wastewater treatment options, namely biological treatment, electrolytic dissociation and electrochemical reduction, can satisfy these demands and have gained considerable attention for recalcitrant wastes treatment. While pentachlorophenol has been illustrated to be degraded in BCMFCs, much effort is still needed to focus on its possibility for degrading other chlorophenols (CPs) due to the practical existence of multiple CPs as well as the necessity of robust biocathode MFCs for diverse CPs degradation. In this study,4-CP,2,4-DCP and2,4,6-TCP were respectively used as a final electron acceptor in BCMFCs and CPs degradation rate, power production, as well as coulombic efficiencies (CEs) were assessed. In order to further improve CPs degradation rate, inductive effect was explored based on the addition of2,4,6-TCP to the biocathode acclimated through2,4-DCP.BCMFCs achieved a degradation rate of5.6±0.7x10"3mmoM/’-h’1for4-CP,5.1±0.9x10"3mmol-U’-h"1for2,4-DCP, and1.6±0.4*10"3mmol-L"1-h"1for2,4,6-TCP. In terms of electricity generation,4-CP ranked the most followed by2,4-DCP and2,4,6-TCP. An anoxic condition resulted in electricity increase from2.0W/m3to3.9W/m3, degradation decrease from5.1x10’3mmoM/’-h’1to3.0x10"3mmol-L/’-h"1, and CEs abatement from19.1±0.9%to3.4±0.4%. The addition of2,4,6-TCP to biocathode acclimated through2,4-DCP led to1.5W/mJ decrease of voltage output whereas the degradation rate of2,4,6-TCP exhibited4.1±0.1x10"3mmol-U’-h"1in comparison with5.1±0.9x10"3mmol-L"I-h"1for2,4-DCP. The degradation rate of2,4,6-TCP was successfully enhanced2.6times, indicating this inductive positive effects on2,4,6-TCP degradation. A mixed2,4-DCP and2,4,6-TCP resulted in a slight decline of power density compared to the CPs only. However, a total degradation rate of5.0x10"3mmol-U’-h"1including2,4-DCP and2,4,6-TCP was achieved, in which2,4-DCP degradation rate is lower than the2,4-DCP degradation only and2,4,6-TCP degradation rate is higher than the2,4,6-TCP degradation only.