An Anode Optimization Experienmental Study Of Microbial Fell Cell

Microbial fuel cell is a cutting-edge electrical energy production and wastewater treatment technology that uses organic matter in wastewater to obtain electrical energy.It was developed by the cross-fusion of materials science,microbiology,biochemistry,electrochemistry,mass transfer,fuel cell science and new energy technology.Since microbial fuel cells are an interdisciplinary technology,systematic learning and understanding of interdisciplinary knowledge are of great significance for the study of performance optimization of microbial fuel cells.Firstly,this research summarized the basic theoretical knowledge related to microbial fuel cells,and then used the relevant theoretical knowledge as a guide to determine the specific research direction of anode optimization.The summary of the existing theoretical theory of MFC includes four parts.One is the thermodynamic basis of the microbial fuel cell.The theoretical maximum voltage was calculated for the anode and cathode used in the experiment in this study,and it was compared with the actual measured voltage.The second is the electricity production mechanism of microbial fuel cells.This includes the biological oxidation process inside the electro-producing bacteria and the electron transfer mechanism outside the electro-producing bacteria.The third is the electrochemical polarization phenomenon of microbial fuel cells.From various types of internal resistance sources and components,effective ways to reduce internal resistance were analyzed.The fourth is the description of the mass transfer phenomenon inside the microbial fuel cell.In this study,two modified materials for MFC anode were prepared.The experimental results showed that both can effectively improve the performance of MFC.The specific research contents are as follows:（1）Self N-doped nitrogen carbon nanosheets（N-CNS）with high specific surface area were prepared by one-step carbonization and KOH activation of dandelion seeds with high nitrogen content.In addition,porous carbon（N-UA-CNS）was prepared by directly carbonizing dandelion seeds without KOH activation.Both of the above were used for MFC anode carbon cloth modification materials,and the material properties and the impact on MFC performance were characterized.Surface morphology tests showed that both N-CNS and N-UA-CNS had a large number of porous structures,and the pore size of N-CNS was more suitable for the attachment and growth of exoelectrogens than N-UA-CNS.At the same time,the BET specific surface area of N-CNS was 2107.5m²?g^-1,which was greater than the BET specific surface area of N-UA-CNS.EIS test showed that the ohmic internal resistance between the two was not much different,and the activation impedance of N-CNS-CC was 2.7Ω,and that of N-UA-CNS-CC was 4.0Ω,both of which are smaller than that of blank carbon cloth（CC）.N-CNS-CC anode MFC showed obvious advantages in starting time,output voltage stability and maximum output voltage,and the maximum power density was 1122.41m W?m^-2,which was 1.3 times higher than that of the N-UA-CC anode MFC and 1.6times higher than that of the CC anode MFC.The above results indicate that N-CNS can significantly improve the performance of MFC anodes.However,the biomass raw materials are cheap and easily available,and can achieve the purpose of self-doping nitrogen without additional steps,so the practical application prospect is broad.（2）A porous carbon material（PC）was prepared using zeolite MCM-22 as a template,nickel ions as a catalyst,and sucrose as a carbon precursor.In addition,the intermediate product（Ni-MS-PC）of the template material that has not been etched by the mixed acid solution was retained.Both of the above were used in MFC anode modification materials,and the material properties and the impact on MFC performance were characterized.The surface morphology test showed that the PC had a micron-scale sheet structure.The BET specific surface area of PC was 578.66 m²?g^-1,which was higher than that of Ni-MS-PC.The EIS test results showed that the PC-modified carbon cloth（PC-CC）and Ni-MS-PC-modified carbon cloth（Ni-MS-PC-CC）had activated internal resistances of only 2.6Ωand 3.2Ω,both of which were less than CC.This showed that the modified material can effectively reduce the activation energy barrier of CC participating in the redox reaction.The COD removal rate of the anode chamber effluent of PC-CC anode MFC was 89.69%,and that of Ni-MS-PC-CC anode MFC was 81.23%,which was both higher than that of CC anode.The maximum power density of the PC-CC anode MFC was 900.94m W?m^-2,and it was increased by 9.00%compared to that of the Ni-MS-PC-CC anode MFC.The above conclusions indicated that PC as an MFC anode modification material could exhibit excellent performance.The template method has a simple preparation process and the possibility of being enlarged.It is a promising MFC anode modification material.