Study On Electrochemical Characteristics And Microbial Activity In Suspended Microorganism Electrochemistry System

In this paper,the electrochemical characteristics and microbial activity of suspended microorganism electrochemical system were studied to study the limiting factors of microbial fuel cell power efficiency and the interaction between microorganisms and electrodes in the field of microbial electrochemistry.Three kinds MFC that is micro MFC,H type dual chamber MFC and suspension type(flow electrode)MFC were built.The maximum power output under stable condition is measured respectively,and the internal influence factors of MFC power generation capacity are analyzed.Besides,the effects of direct current electric field on cell viability and physicochemical properties of suspended Shewanella(electrogenerated bacteria)and Escherichia coli(non electrogenerated bacteria)is studied.The maximum power density of the micro MFC,H type dual chamber MFC and suspension type(flow electrode)MFC were 1420mW/m2,370mW/m2 and 3050mW/m2,respectively,and the internal resistance was 640,1120 and 46 ohms respectively.Under the experimental conditions,when the mass fraction of activated carbon is 15%and the carbon black dosage is 1%,the microbial fuel cell reactor with flow electrode has the best electricity generation performance,and in this experiment,the flow rate(2mL/min～6mL/min)is not related to the internal resistance and power generation capacity of the system.Through the analysis of differences in growth patterns and rate of electrogenerated bacteria and non electrogenerated bacteria under different intensity electric fields,it was found that the direct current electric field accelerated the growth of microbes.But the growth of Escherichia coli in the cathode is more and the growth of shewanella in the anode is more.Secondly,there is a significant difference in pH value between media and open circuit.No matter the Shewanella(electrogenerated bacteria)and Escherichia coli(non electrogenerated bacteria)as the culture,the activation internal resistance accounts for a large proportion of the total internal resistance,and the resistance decreases with time.The anode capacitance increases with time,and the anode capacitance is negatively correlated with the resistance.