Electrochemical Performance Of Microbial Fuel Cell Based On Foam Nickel Electrode

Microbial fuel cell（MFC）technologies are a promising and yet completely different approach to wastewater treatment as the treatment process can become a method of capturing energy.MFC is a device that uses microorganisms as a catalyst and generates electricity.The organic carbon source or inorganic substanceis are degraded by enzymes or microorganisms,and the organic matter is converted into electric energy by the metabolism of microorganisms.The main problems that hinder the performance of MFC is the energy is too low to be used directly.The most important factor in the factors affecting MFC performance is the electrode material.Therefore,it is very important to look for inexpensive electrode materials and separation materials,optimize the configuration of the MFC reactor,explore optimal operating conditions to try to improve the electricity production performance of MFC.In addition,by intermittently connecting the resistors and disconnecting the resistors,more power can be generated than under continuous load resistors,but very little is currently being studied.This topic is based on the double-chamber MFC.From the perspective of improving the MFC output,the inexpensive electrode material was used to modify the cathode and anode.The rGO/MnO₂/NF electrode was prepared and characterized by X-ray diffraction（XRD）,Raman spectroscopy and scanning electron microscopy（SEM）.The results showed that the rGO/MnO₂/NF electrode was successfully prepared by the two-step hydrothermal reaction method,and the specific surface area of the electrode was effectively improved.The rGO/MnO₂/NF was applied to the cathode and anode of MFC.The following conclusions are drawn:The rGO/MnO₂/NF anode can effectively increase the MFC output voltage and electricity generation performance.The maximum power density can reach 684 m W/m²,which was 20 times and 2.5 times higher than carbon felt anodes and nickel foam anodes,respectively.The large specific surface area and low electrode internal resistance are the reasons for the accelerated electron transfer process of the anode.After running for 4months,the rGO/MnO₂/NF-MFC voltage dropped by 9.7%,indicating that the rGO/MnO₂/NF anode has better stability.rGO/MnO₂/NF is used in MFC cathodes.It is found that it does not improve the output voltage and power generation performance of MFC,the maximum power density is only 17.8 mW/m².This shows that the pure biocathode is better than biocathode with rGO/MnO₂/NF.The preparation of binderless cathode requires further research and exploration.In addition,we investigated the effect of rGO/MnO₂/NF capacitor anode on MFC performance in transient mode（TSR）and steady state modes.The experimental results showed that the power density in the transient mode（529 mW/m²）is greater than the steady state power density（505 mW/m²）.It is therefore evident that transient-state regulation did hold the potential to further enhance the power generation of MFCs with capacitive anodes.The reason is that the same anode with different potentials may promote the participation of more cytochromes,which can enhance the MFC’s electrical production performance in the TSR mode of operation.The TSR mode parameters have been optimized to achieve the best MFC performance in the TSR mode.It was found that when the external resistance is 500Ω,the duty cycle is 67%,and the frequency is 1Hz,the MFC has the largest power density.The long-term operation results showed that the power density in the TSR mode is significantly greater than the power density in the steady state mode.The results of this study indicate that the composite electrode has been successfully applied to MFC to improve its electrical production,while optimizing the TSR mode parameters and further improving the MFC performance.The results of this study also provide the possibility of improving the performance of capacitive anode-based MFC in TSR mode.