Power Generation Of Sediment Nicrobial Fuel Ceel Based On Substrates Types

In recent year, microbial fuel cell (Microbial Fuel Cell, MFC), as an advanced technology utilizing waste biomass directly for power generation, has gained extensive attention. Sediment MFC (SMFC), a sort of membrane-less MFC, which can be applied to water remediation and cost less without addition of electron acceptor or oxygen-supplier and secondary pollution, appeals to more and more researchers. In this study, the effect of substrate type on the performance of SMFC in sequencing batch is investigated in terms of cell performance, behavior of power generation and character of bioflim on anode electrode, with glucose, sodium acetate, cyanobacteria acidogenic fermentation liquid and cyanobacteria as substrates, respectively. Furthermore, the characteristic of electron transfer in anode is analyzed combined with cyclic voltammetry (CV). This will enrich the theory connotation of SMFC and be a helpful complement to the recycling technology of cyanobacteria so that it is worthy of great academic value and application perspective. The major contents of research and results are as follows:(1) The variation of substrate degradation is positively correlated with the power density. Both the maximum power density (63.24 mW/m2) and the substrate degradation (72.6%, 0.607 kgCOD/m3·d) of SMFC with cyanobacteria acidogenic fermentation liquid as substrate are the highest, followed by the SMFCs with sodium acetate (50.92 mW/m2,72.0%,0.573 kgCOD/m3·d) and glucose (42.14 mW/m2,53.6%,0.427 kgCOD/m3-d). The results show that SMFC utilizing cyanobacteria acidogenic fermentation liquid for power generation is feasible.(2) The substrate type affects microorganism metabolism activities and the growth of biofilm on anode electrode and results in the variation of activation resistance, mass transfer resistance, cathode, anode potential and power output of SMFC eventually. SMFC using cyanobacteria acidogenic fermentation liquid as substrate shows the lowest anode potential (-427 mV), the highest cathode potential (164 mV), the highest cell potential (591 mV) and the lowest internal resistance (461Ω), therefore the power output (71.77 mW/m2) is the highest.(3) Total extracellular polymeric substances (EPS) of SMFC taken glucose as substrate is the highest (19.28 mg/gVS) and total EPS of control SMFC (17.44 mg/gVS) is second only to that of glucose system because of autophagocytosis. Cyanobacteria acidogenic fermentation liquid leads to lower mass transfer resistance and total EPS of SMFC with it as substrate is 16.99 mg/gVS. It's demonstrated that effect of activitation resistance is greater than ohmic resistance in biofilm on anode electrode of SMFC because biomass of SMFC with acidogenic fermentation liquid is the largest (7.46μgP/g carbon felt) and internal resistance is also the lowest (461Ω). Besides, the electrochemical activity of biofilm on anode electrode of SMFC with acidogenic fermentation liquid is the strongest (0.077 A at 0 V) and bacilli occupy the dominant position of microbial community.(4) The analysis on the characteristic of electron transfer in anode of SMFC based on substrate type shows that electron is transferred to anode electrode by adsorbing to the surface of electrode and forming biofilm in SMFC. The current output of SMFC can be increased by optimizing the capability of biofilm forming on anode.