| Microbial fuel cell(MFC)degrades organic wastewater and generates electricity simultaneously through microorganisms.Anode performance is the key to affect the power output of MFC.In this paper,the landfill leachate was treated with MFC anode modified by manganese dioxide and polyaniline.The effects of substrate concentration,temperature and applied current on the electrical production performance of modified MFC and the physical and chemical properties of landfill leachate were investigated.The main results are as follows:(1)MnO2 and MnO2/PANI modified anodes were prepared.XRD results showed that manganese dioxide was attached to the electrode.SEM results showed that the modified anode surface was rougher and more conducive to microbial adhesion.EIS results showed that the charge transfer resistance of MnO2 and MnO2/PANI anodes were 3.62Ω and 7.32 Ω respectively,which decreased by 65.5%and 30.2%compared with 10.49 Ω of unmodified electrode,CV results showed that there was only one reduction peak at MnO2 electrode,and the peak current was 0.046A.There were two oxidation peaks and one reduction peak at MnO2/PANI electrode.The oxidation peak current was 0.035A and 0.080A respectively,and the reduction peak current was 0.073A,which was 58.7%higher than that of MnO2 electrode.(2)The power generation performance of MFC under three different substrate concentrations of 1200mg/L,2000mg/L and 3000mg/L landfill leachate was investigated.The results showed that the voltage value and power density of unmodified anode MFC were the highest under the substrate concentration of 3000mg/L,and the maximum voltage and power density of MnO2,MnO2/PANI and unmodified MFC were 385mV,338mVand 237mV,739 mW/m3,549 mW/m3 and 372mW/m3,respectively.The substrate concentration has little effect on the modified MFC and has a greater effect on the unmodified anode.This is due to the high catalytic activity of manganese dioxide and polyaniline,which makes the microorganism use the substrate more efficiently.However,under the condition that the electricity producing microorganism on the unmodified anode is not in a competitive advantage,increasing the substrate concentration can rapidly increase the microbial metabolic rate,So as to improve the power generation efficiency of MFC.When the substrate concentration is 1200mg/L,the removal rates of COD and ammonia nitrogen by MFC are the highest.The removal rates of COD and ammonia nitrogen are 92.3%,89.3%and 88.7%respectively,and 91.0%,86.9%and 82.5%respectively.The power generation performance of MFC at 20℃,25℃ and 30℃ was investigated.The results showed that when the temperature was 25℃,the operation cycle of MFC was the shortest,and the cycles of MnO2,MnO2/PANI and unmodified anode MFC were 516 h,447 h and 432 h respectively.When the temperature was 20℃,the operation cycle of MFC was relatively long,645 h,519 h and 600H respectively.At 30℃,the highest power densities of MnO2,MnO2/PANI and unmodified anode MFC were 574.59 mW/m3，600.61 mW/m3 and 320.97 mW/m3 respectively.(3)The power generation performance of MFC under three different additional current conditions of 3.6×10-4A,7.2×10-4A and 10.8×10-4A was investigated.The three cycle lengths were 404h,239h and 207h respectively,and the maximum coulomb efficiency was 3.0%,1.1%and 1.0%respectively.The results show that the three cycle lengths are 404h,286h and 188H respectively,and the maximum coulomb efficiency is 3.01%,0.97%and 3.29%respectively.The results of Fourier transform infrared spectroscopy and three-dimensional fluorescence spectroscopy showed that macromolecular organic substances in MFC effluent were removed,and the fluorescence characteristic peak intensity representing tyrosine like substances,tryptophan like substances,fulvic acid like substances and soluble microbial degradation products in EEM decreased from 0.159/0.168/0.220/0.182 Ru in landfill leachate to 0.119/0.103/0.105/0.097Ru,It shows that different organic substances in landfill leachate have been degraded and removed to varying degrees.The results of strain analysis in MFC under three different operation modes show that the dominant bacteria in MFC are mainly Acinetobacter haemolyticus,accounting for 53.96%and 31.57%respectively in the anode solution of MFC under normal operation and open circuit operation.The dominant archaea are mainly methanogens Soxhlet,accounting for 94.51%at most on the anode of MFC under normal operation.Fig43,Tab5,Ref115... |
PDF Full Text Request