Research Progress on Degradation of Organic Pollutants By Soil Microbial Fuel Cells: Utility of Carbon-based Electrodes

Various organic pollutants in soil not only affect agricultural production and food safety, but also directly threaten human health and ecological environment. Microbial remediation is widely used, but its application is confined to the lack of electron acceptors, low efficiency, and poor broad-spectrum. Soil microbial fuel cell (SMFC) is a rising solution. The anode plays the part of an electron acceptor and conducts bioelectricity generated by microorganisms to decompose organic pollutants. While degrading pollutants, it can also generate bioelectricity to reduce energy consumption. In this paper, the research progress of soil microbial fuel cells and their carbon-based electrodes in recent years is reviewed, and the mechanism of bioelectrochemical reaction is introduced. Firstly, the structure and composition of carbon-based electrodes are compared and discussed, and the degradation rate is analyzed. Secondly, the electrochemical properties of SMFC systems composed of different carbon-based electrodes are described. At present, most of the research is concentrate on the modification of carbon-based electrodes to increase the degradation rates and electron conduction efficiency of pollutants. However, it is necessary to focus on the battery frame, multi-electrode SMFC and other directions, combined with nanomaterials, photoelectric technology to improve the degradation rate and power generation density. In the future research, the large-scale deployment of SMFC should be considered to put SMFC into practical application.