Effects Of Pyroligneous On Performance And Anode Bacterial Community Of Microbial Fuel Cell

Microbial fuel cell(MFC)is the electrochemical system with microorganism as catalyst to convert chemical energy of organic compounds into electric energy.Anode bacterial community is the core factor of performance of MFC.This research aims to change anode bacterial community by means of pyroligneous addition,which can subsequently improve the efficiency of the MFC.Therefore pyroligneous can be used as a reaction promoter with the understanding of the degradation mechanism of pyroligneous in MFC.The research had firstly compared the performances of single-chamber air-cathode MFC and two-chamber air-cathode MFC.The results showed that the performance of two-chamber air-cathode MFC is better,so two-chamber air-cathode MFC was selected for further reaearch.The electricity generation from pyroligneous,the degradation mechanism of pyroligneous,and the anode bacterial community were investigated in this study.Electricity generation by using pyroligneous with different concentration was investigated,The results show that the electricity generation of P1-MFC was the highest,the current density was between 1.0 A/m~2 and 1.2 A/m~2,the maximum power density was 0.377W/m~2,and the coulombic efficiency(CE)was 15.04%.The electricity generation of P1-MFC was the lowest,the electric current density always showed a declined tendency with the minimum electric current density of 0.174 A/m~2,the maximum power density was 0.037W/m~2 and CE was 19.27%.The electrochemical analysis revealed that the performance improvement of P1-MFC was achieved through the reduction of reaction resistance.The degradation of pyroligneous in MFC was investigated.The results show that the COD remove rate of B-MFC was the highest of all experimental groups but the CE of B-MFC was lower,the results suggests that pyroligneous addition can enrich anode electricigens.Some constituents in pyroligneous were degraded to acetate and converted into electricity,and that the rising point of acetate in P1-MFC group showed the best performance within all groups,the constituents which can be degraded to acetate in pyroligneous were preferentially degraded.The degradation rates of the total phenol in three groups of pyroligneous addition were 83.95(P1-MFC),81.11%(P2-MFC),and 57.65%(P3-MFC)respectively.With the concentration increase of pyroligneous addition,the degradation rate of the total phenol reduced.The change of anode bacterial community was investigated.The results show that the pyroligneous addition with the concentration of 1 g/L can promote the growth of anode electricigens,however,the pyroligneous addition with the concentration of 3 g/L can kill anode electricigens,and in turn reduce the COD removal of reactor.The pyroligneous addition with the concentration of 1 g/L and 2 g/L increase the relative abundance of Geobacter,but the lower density of anode flora in P2-MFC(2 g/L)limited the performance of the reactor.Above all,The pyroligneous addition with the concentration of 1 g/L promoted the growth of anode electricigens,increased the relative abundance of Geobacter,reduced reaction resistance of the reactor,and in turn promoted the performance of the reactor.The pyroligneous addition with the concentration of 2 g/L and 3 g/L both reduced the density of anode flora which affected the performance of the reactor.