Optimization Study On The Electrode Materials Of Microbial Fuel Cell

Microbial fuel cell (MFC) is a kind of clean energy technology which can simultaneously treat wastewater while generating electricity. It can save the cost of sewage treatment and improve energy efficiency, so it has good prospects for development. However, due to the low performance of electricity production and high cost of the electrodes, the technology still has not been applied in practice. In this paper, two-chamber MFC was selected as experimental reactor. Then screened the carbon-based anode and cathode materials and modified it with nanoparticles to improve the performance of MFC’s electricity production.First of all, carbon brush was selected as carbon-based anode materials to modify because of its better power generation property by screening the carbon-based anode materials. Then using CNTs, LiMn2O4 and Fe3O4 nanoparticles to modify the carbon brushes respectively, and used it as the anode of MFC to research its electricity generation. The results showed that the anode modified by three nanoparticles made the stabilized voltage of the MFCs increase with 7.9%,21.8%,27.8% respectively, power density increased with 1.9% 27.5% 37.2% respectively, the internal resistance decreased with 15.6%,18.4%,24.7% respectively, coulomb efficiency improved with 8%,21.8%,27.8% respectively. And the modification with nanoparticles can accelerate the starts of MFCs. From the experimental results, the anode modified with Fe3O4 nanoparticles can effectively improve the performance of MFC’s electricity production.Using carbon brush modified with Fe3O4 nanoparticles as anode of MFC, and further optimized the cathode material. Carbon felt was selected as carbon-based cathode materials to modify because of its better power generation property by screening the carbon-based anode materials. Then using CNTs, LiMn2O4 and Fe3O4 nanoparticles to modify the carbon felt respectively, and used it as the cathode of MFC to research its electricity generation. The results showed that the anode modified with three nanoparticles made the stabilized voltage of the MFCs increase with 3.5%,4.9%,15.2% respectively, power density increased with 6.5%,6.6%,30.8% respectively, the internal resistance decreased with 3.3%,3.9%,13.2% respectively, coulomb efficiency improved with 3.5%,7.4%,32.6% respectively.Through the selection and optimization of the anode and cathode materials, Finally, the MFC which used carbon brush modified with Fe3O4 nanoparticles as anode and carbon felt modified with Fe3O4 nanoparticles as cathode achieved a better electricity production results. Its stable output voltage reached 326mV, the maximum power density attained 302.3mW/m2, coulombic efficiency increased to 8.66%, and the internal resistance of the battery is reduced to the 489.2Ω. This indicates that the modifications of cathode and anode resulted in great improvement on the MFC’s performance.Further experiments studied the community structure of the anode and cathode chambers sludge and inoculated sludge by using MiSeq sequencing. The anode and cathode chambers inoculated sludge and its community structure were studied. The results showed that the species and abundance of the microorganisms associated with electricity production in the the anode chambers were higher than other sludge samples, and the microbial community structure is similar to both anode chamber sludge. But the abundance of the microorganisms associated with electricity production on the surface of the carbon brush anode modified with Fe3O4 nanoparticles is higher than the unmodified carbon brush anode. This indicates that the modification of nanoparticles can help exoelectrogens on the surface of electrode materials. This’s why the modified anode materials can improve the electricity production performance of MFCs. The results showed that the anode chamber sludge associated with electricity production of microbial species abundance were higher than other clay-like, microbial community structure is similar to both the anode chamber, but after Fe3O4 nanoparticles modified carbon brush anode surface and produce electricity related microbial abundance higher than unmodified anode.