| Landfill leachate,generated from disposal of municipal solid waste,contains high concentrations of a wide variety of organic and inorganic contaminations,ammonium,phosphate and heavy metal ions.Soil resources and water resources security would be seriously destroyed if landfill leachate is discharged without treatment.Compared with young landfill leachate,the composition of aged landfill leachate is more complex,and it's difficult to degrade aged landfill leachate.Microbial fuel cell(MFC),which is used to produce electricity while achieving wastewater treatment,is a new technology of sewage treatment.Microbes are used as catalyst of both anode chamber and cathode chamber in bio-cathode MFC,so both of the two chambers have the ability of pollutant removal.Bio-cathode MFC become a new direction for the treatment of aged landfill leachate,for it can reduce the cost of MFC and improve the containment removal rate.Dual-chamber bio-cathode MFCs were constructed by using carbon felt and carbon cloth as electrode materials and aging landfill leachate as anolyte,and investigated their electricity production and treatment performance to obtain the best performance combination of electrode material.Meanwhile,MFCs with the best combination of electrode material,which modified with MnO2/rGO and Pt/C,were also constructed to obtain the better performance of MFC cathode catalyst.Electrode material is an important factor affecting MFC performance.Four groups of dual-chamber bio-cathode MFCs were constructed to test the effect of electrode material on MFC performance,and the electrode materials of MFCs were respectively carbon felt as anode and cathode,carbon felt as anode and carbon cloth as cathode,carbon cloth as anode and carbon felt as cathode,carbon cloth as anode and carbon cloth as cathode.The output voltage of MFCs were 275,249,294 and 259 mV,the maximum power densities were 87.00,71.62,95.31 and 78.70 mW/m3,the internal resistance were 347,332,325 and 308 ?,respectively.The removal rates of chemical oxygen demand(COD)were 48.07%,45.93%,58.78% and 53.64%,and the removal rates of ammonia were 54.00%,47.99%,74.38% and 63.83%.The results show that the electricity production and treatment performance of the MFCs using carbon felt as cathode materials are both better than those of the MFCs using carbon cloth as cathode materials when the anode materials are same.Meanwhile,when the cathode materials are same,the electricity production and treatment performance of the MFCs using carbon cloth as anode materials are better than those of the MFCs using carbon felt-cathode MFC.Cathode material is the main affection factor of MFC electricity performance,while anode material affects the contamination removal rate more.Cathodic reaction is an important factor affecting the performance of MFC.Four groups MFCs were constructed to test the effect of catalyst on MFC performance,and the cathode of MFCs were modified by 0 mg/cm2 MnO2/rGO,0.5 mg/cm2 MnO2/rGO,1.0 mg/cm2 MnO2/rGO and 0.5 mg/cm2 Pt/C,respectively.The output voltage of MFCs were 322,351,372 and 384 mV,the maximum power densities were 102,143,194 and 217 mW/m3,the internal resistance were 396,310,264 and 239 ?,respectively.The removal ratios of COD were 47.61%,53.32%,58.68% and 61.66%,and thoses of ammonia were 72.69%,75.42%,76.64% and 78.64%.Compared with non-modified cathode MFC,MFCs modified with catalysts can significantly improve the electricity production and contaminants removal rates.It's inferred that the cathode modified with MnO2/rGO can improve MFC performance.When the MnO2/rGO loading was 1.0 mg/cm2,the output voltage was higher 50 mV than that of non-modified cathode MFC,the maximum power density was increased by 90.2%(nearly one time),the removal rate of COD was increased by 23.3%.Moreover,the performance of MFC with 1.0 mg/cm2 MnO2/rGO cathode is similar to that of MFC with 0.5 mg/cm2 MnO2/rGO cathode,but the cost of the late greatly reduced.It's indicated that MnO2/rGO is a lower cost MFC catalyst with excellent performance. |
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