Study On The Performance Of Polymer Modified Anode In Benthic Sediment Microbial Fuel Cells

With the improvement of human living standard and the continuous development of society and economy, more and more environmental problems cause people’s attention, such as energy shortage, environmental pollutions and destructive phenomenon. Looking for new efficient and environmental protective energy becomes an imminent demand.As a new type of energy device——microbial fuel cell (MFC), it produces electricity by the way of catalyzing and degrading organic matters with its own metabolism of the electro-genesis microorganism. The benthic sediment microbial fuel cell (BMFC) is one specific type of MFCs that the electrons produced by electro-genesis microorganism are passed to the cathode through the anode embedded in sediments and the external circuit. There, the electrons are combined to water with the protons from anode and the oxygen in sea water. It provides a new way for the utilization of the sea sediment. Meanwhile, due to the simple battery configuration and its environmental friendliness, these result in the extensive concern of the researchers in related field.However, the energy output of the BMFC is so lower that it limits the BMFCs’ practical application. Among various kinds of factors, the low electron transfer efficiency between the anode and the electro-genesis microorganism is a key influence factors. Therefore, to address the problem many researches focus on improving the performance of the anode. As a new type of modified anode materials, conductive polymers have caused extensive concern of the academia. This paper mainly discusses the modified anode how to influence on the properties of the BMFCs. The results provide a theory basis for the practical application of the BMFCs and their conclusions are as follows:Polyaniline film layer is compound on the surface of glassy carbon electrode using the method of electrochemical polymerization, and the electrochemical properties of polyaniline compounded under different polymerization potential, acid, pH and concentration of monomer are discussed. The results showed that under the conditions of 0.5 M H2SO4 aqueous solution, scanning range from 0.2 V to 0.9 V, monomer concentration 0.05 M, the polyaniline shows better electrochemical activity.A PANI modified electrode which uses the way of electrochemical deposition is utilized as the anode of the BMFCs. The results indicate that by electrodeposition, some conductive polyaniline are adhered to the surface of the anode so that its capacitance increases significantly. The maximum power density of 160.1 mW·m-2(current density is 400.0 mA·m-2) is more than 2 times higher than that of the unmodified anode. Finally, we analyze the doping and de-doping mechanism for its high performance in electron transmission of the BMFCs.A PANI-PPy modified electrode which uses the way of electrochemical deposition is utilized as the anode of the BMFCs. The results indicate that by electro-deposition, some conductive PANI and PPy are adhered to the surface of the anode so that its capacitance increases significantly. The maximum power density of 213.4 mW·m-2(current density is 491.8 mA·m-2) is about 2 times higher than that of the unmodified anode. Finally, we analyze the possible mechanisms for its high performance in the BMFCs.