Simultaneous Decolorization Of Congo Red And Electricity Generation In A Two-Chambered Microbial Fuel Cell

A H-type two-chambered microbial fuel cell (MFC), using anaerobic activated sludge as inoculums, was constructed to investigate the effect of sodium acetate and Congo red as co-substrates on electricity generation of MFC and decolorization and COD removal of MFC anode chamber, and the effect of ammonium persulfate and potassium ferricyanide as cathodic electron acceptor respectively on the performance of MFC.After several cycle gradual addition of acetate, MFC was successfully started up. Then the effect of initial acetate and Congo red and different external resistance on electricity generation of MFC and decolorization and COD removal of MFC anode chamber were studied. The results show that acetate and Congo red can be used by microorganisms to generate electricity and decolorization. The voltage output of MFC increases from213.2mV to404.1mV and the power output increases from65.53mW/m3to80.62mW/m3when concentration of sodium acetate changes from0.5g/L to2.0g/L. The voltage output and power output can be increased with higher acetate concentration, but is not increased infinitely. With concentration of acetate increasing, Congo red decolorization are all greater than70%, COD removal rate are all higher than80%, but the difference is not significant.Activity of current producing microorganisms is kept down by the addition of Congo red, but the final voltage output as well as Congo red decolorization and COD removal are not affected obviously. The voltage output of MFC are all above430mV and the power output are all about70%～80%. The higher the concentration of Congo red, the balance time of decolorization and COD removal will be prolonged relatively.MFC was restarted up. Then the effect of different concentration of ammonium persulfate and potassium ferricyanide on electricity generation of MFC and COD removal of MFC anode chamber were investigated. The results show that when the volume of the cathode and athode is equal and the external resistance is1000Ω, ammonium persulfate (10.0g/L) as the electron acceptor has the maximum open circuit voltage of1029.0mV, the minimum internal resistance of982.5Ω and the maximum power output of385mW/m3.Potassium ferricyanide (10.0g/L) as electron acceptor has the maximum open eircuit voltage of711.8mV, the minimum internal resistance of2339.4Q and the maximum power output of78mW/m3.The power output is influenced by the volume ratio of the anode and cathode to a certain extent. With the concentration of electron acceptor, anode maximum COD removal first increases, then decreases When the volume ratio of cathode and anode is less than1or equal to1, the power output is higher than that more than1.