Effects Of Electrode And External Resistance Change On Performance Of Single Chamber Microbial Fuel Cells

Aging landfill leachate has higher ion concentration,alkalinity and high concentration of total phosphorus,ammonia and COD.Microbial fuel cells and microbial electrolysis cells can effectively remove organic pollutants from the aging landfill leachate,while microbial fuel cells can convert chemical energy in the substrate into electrical energy.However,low removal rate of pollutants and low production capacity are the main reasons to restrict the practical application of microbial fuel cells.And so,the single-chamber membrane-free air-cathode microbial fuel cells have been built to explore the effect of electrode area,anode modification,and series electrolysis cell substituted for external resistance on the performance of electricity generation and the substrate removal efficiency of pollutants.Single chamber membrane free air cathode microbial fuel cells were constructed to treat the aging landfill leachate,and the effects of electrode surface area on the removal of pollutant and the electricity generation performance of microbial fuel cells were studied.The anode and cathode surface area of the three sets of cells are 7.065/7.065cm~2,12.56/7.065 cm~2 and 12.56/3.14 cm~2,respectively.The results illustrate that the output voltages of MFCs are respectively 105,160 and 50mV,the maximum electric power density of 33.7,96.4 and 5.7mW/m~3,and the resistance of 577.6,433 and 914?.COD removal rate are respectively 21.4%,18.5%and 47.6%,and ammonia removal rate are 58.3%,73.9%and 34.2%.The pH is increasing while the conductivity is dropping.The larger electrode area can increase the output power of MFC to a certain extent.And it is beneficial to the denitrification reaction,but there is a certain retroaction to the degradation of COD.Constructed air-cathode single-chamber microbial fuel cells by using the aging landfill leachate as substrate,to study the influence of anode modification ways on the electricity productivity and pollutions removal efficiency of aging landfill leachate.After carbon felt modified with heating,concentrated nitric acid,acidic potassium dichromate and mixed acid,results show maximum outputs power density of cells are respectively increased by 104%,241%,51%and 181%,removal ratios of ammonia increased by 22.2%,21.8%,2.3%and 47.3%,but removal efficiency of COD no significantly changed.Constructed systems include air-cathode single-chamber microbial fuel cells and microbial electrolysis cells,which use the aging landfill leachate as substrate.The three systems respectively are a microbial fuel cell connect with resistance,a microbial fuel cell connect with a microbial electrolysis cell,and two microbial fuel cells connect with a microbial cell.The results illustrate that the output voltages of systems are respectively 146,421 and 253mV,removal efficiency of COD is higher in MFCs of connecting system,whereas removal efficiency of COD is lower in MECs.Removal ratios of ammonia in MECs reach up to 96.2%and 90.8%.