Study On Anode Modification And Performance Of Microbial Fuel Cell

The global fossil energy is consumed rapidly as an non-renewable energy,and the exploitation and utilization caused serious pollution to the environment.Based on the above reasons,microbial fuel cells is one of the most exciting energy technologies to transfer chemical energy into electrical energy.In addition,microbial fuel cells using sewage as the fuel has relatively low corrosion and safety activity.However,the slow electrode kinetics and low power densities inhibit its application.The restraining factor includes substrate concentration,reaction temperature,microbial species,the battery internal resistance,reactor configuration,electrode materials,membranes,etc.The research of the microbial fuel cell has focused on the electricigens.The anode is the important factor for the adsorption,living,electron transmission of the electricigens.Therefore,the aim of the paper is to study the treatment of the anode and the influence to the activity of the cell.In the paper,a dual-chamber microbial fuel cell?MFC?is constructed to study the activity of the anaerobic bacteria mud in Taiyuan.At first,temperature and concentration are discussed for operation parameters of MFC.Setted three different temperature like 25?,35?,45 ? to operating the cells and analysed the electrochemical testing and power performance,we found that the output power density reached largest in 35?,meanwhile,the internal resistance was minimum.So,35 ? is the most suitable temperature for exoelectrogen survive and metabolism and lead to best electrochemical activity.And then we operated cells of three different concentration of acetic acid sodium like 0.5g/L,1.0g/L,1.25g/L under 35?,the results showed that the output power was not increased with the add of concentration of sodium acetate,it reached maximum in 1.0g/L.Due to the saturation effect made the power output declined and internal resistance increased,thus,the optimum parameters were 1.0g/L and 35 ?.Next,three different volume ratio?1:3,1:1,3:1?of nitric acid and hydrogen peroxide in mixture were used to proceed hot chemical modification of anode carbon felt.Accessed different double chamber microbial fuel cells with the modified and unmodified anode at the same time,compared the four cells performance via manual and electrochemical test.It shows that the cell start time of modified by mixed oxidant significantly shortened,combined FTIR Spectromete with hydrophilic test of carbon felt showed that different degrees increased of oxygen containing functional groups made the exoelectrogen easier to reproduce and adhesion.While the volume ratio attached to 1:1,the anode processing effect was Performance best,the highest power density was 758.2mW/m2,increased by 51.1%then the unmodified anode MFC?386.76mW/m2?.At the same time,internal resistance was reduced,EIS results showed that the internal resistance was minimum with the ratio reached 1:1 of HNO₃ and H₂O₂,the lower internal resistance increased its power output and accelerated the electrons transfer efficency between microbial cells and the surface of anode.Finally graphite oxide prepared by conventional Hummers method,using cyclic voltammetry?scanning range is 1.6V-0V,sweep speed of 5mv/s?reduced the oxide graphite to anode felt then got graphene anode.The power density of graphene anode MFC?CC-G?improved 2 times then undecorated carbon felt anode?CC?,internal resistance decreased from 486? to 120.6.?.The surface of modified anode materials were characterized by SEM,the results showed that the traditional three electrode system sedimentary graphene can be evenly attached on the carbon felt,its high conductivity made the transmission speed increaced between the bacteria and electrode,the resistance reduced,so as to improved the electrochemical performance of MFC.