Studies On The Performance And Pollutant Removal Of Microbial Fuel Cell With Polymer Modified Anode

Microbial Fuel Cell(MFC)can oxidize and degrade various organic substances in the wastewater,and generate electricity simultaneously by using the microbe in anode chamber,which has received great attention of international and domestic academics recently.In this paper,MFCs were constructed with the conductive polymer as anode and their performance of power generation and energy storage was studied,while the processing pollution and electricity production synchronously were also investigated.An nitrogen doping carbon nanotubes/sponge(NCNT/S)was prepared as substrate.On this basic,the polyaniline electrode(PANI/NCNT/S)and chitosan-nitrogen doping carbon nanotubes-polyaniline electrode(CS-NCNT-PANI/NCNT/S)were prepared though in situ growth method.Three electrodes were applied to MFC anode,the maximum power densities and internal resistance of each MFC were 2601.00/131.36(NCNT/S),3080.25/123.67(PANI/NCNT/S)and 4293.56mW/m~3/84.97?(CS-NCNT-PANI/NCNT/S).When charging60min and discharging 90min,the storage charges were 455.96,2169.48 and 3344.98C/m~2,respectively.The anolyte COD removal rates of the three MFCs operating at 65 h were:74.07%,92.59%,and 95.37%,respectively.These three MFC on the degradation of organic matter conformed to first order kinetics equation.The experiment of degrading wastewater of methyl orange by the above MFCs explored that MFC equipped with CS-NCNT-PANI/NCNT/S had superior performance in decolorizing degradation and electricity production synchronously.Therefore,we toke more experiment on this MFC:As the concentrations of methyl orange were 0,50,100 and 200 mg/L,the decolorization and power generation performance of MFC decreased with the increase of dye concentration,and the coulombic efficiency of MFC also decreased,which were 20.37%,19.21%,19.02%and 16.02%.And the increased concentration of sodium acetate would enhance the performance of electric production and decolorizing degradation in a certain range.In addition,the MFC exhibited the best the performance of electric production and decolorizing degradation at 30?.After coupling the anaerobic system,the performance of electric production and decolorizing degradation were decreased.The microbial community structure of CS-NCNT-PANI/NCNT/S anode was analyzed.It was found that the dominant bacterium of the anode biofilm after long-term decolorization of methyl orange changed from Rhodobacter to Enterobacter.The results show that after long-term domestication,the dominant genus including the electrogenic bacteria and the azo dye decolorizing bacteria has been optimized in the anode biofilm.Polypyrrole/chitosan-CNT(PPy/CS-CNT)electrode was prepared and applied as anode in MFC and the maximum power density of MFC reached to 3844.00 mW/m~3.It can be found from energy storage tests that,at the discharging time were all 40min and the charging time were 10,20,40,80 and 120 min,the storage charge were 10197.93,10438.04,10632.69,11310.13,10603.45 C/m~2,respectively,which showed a trend of decrease after the first increase,it may be due to the open time of MFC was too long that the electrons generated by microbial metabolism had no receptors,which can reduces the biological activity of the electrogenic bacteria.Wastewater treatment experiment for Congo red was employed.As the concentration of Congo red increased,the MFC performance of electric production and decolorizing degradation gradually decreased.And decolourizing perfoemrance of MFC gradually increased with decreasing external resistance.A small amount of existed suspended sludge can accelerate the decolorization process of Congo red.