Influence Of Phenanthrene On The Performance Of Sediment Microbial Fuel Cell

With the rapid development of modern industry, the emission of industrial wastewater isincreasing, resulting in the type and content of organic pollutants in water body alsodramatically climbed up. Those organic pollutants contained many refractory organics, suchas polycyclic aromatic hydrocarbons, heterocyclic compounds, organic chlorides andsynthetic organic compounds etc. They generally contained benzene rings, saturatedlong-chain or branched-chain alkyl groups, and were difficult or not at all to be biologicallydegraded and easily accumulated in organisms. As a new bioenergy conversion process, notonly can microbial fuel cell (MFC) harvest chemical energy from those organic pollutants, butalso effectively dispose them. It made it become a promising technology for the energyshortage and environmental pollution. With the addition of phenanthrene into the anode ofsediment MFC (SMFC), its effect on the electricity generation, electrochemical characteristicsand pollutant removal were investigated in this study. Then, the influence of Tween80on theperformance of phenanthrene-SMFC system was explored. The main research results were asfollows.(1) The effect of different methanogenic inhibition methods on the electricity generation,sludge properties and anodic biomass of SMFCs was investigated. Over four cycles, the cellvoltage reached a steady state. The cell voltage and power density from high to low werechloroform,2-bromoethanesulfonate (BES), control and105oC sterilization, which wasopposite to the apparent internal resistances. The apparent internal resistance and powerdensity of SMFC reactor with chloroform were228.7Ω and9.05mW/m2. The powergeneration was closely related to the anode biomass and sludge characteristics. In the SMFCreactor with chloroform, the content of coenzyme F420was lowest with0.18μmol/g VSS andachieved the best methanogenic inhibition. The anode biomass was highest with10.15μgP/cm3.(2) The effect of phenanthrene on the electricity generation, organic matter removal andanode biomass was explored. With the increase in phenanthrene concentration, the electricitygeneration and pollutant removal were firstly promoted and then suppressed. The SMFCperformance was significantly improved by0.5mg/L phenanthrene. The peak cell voltage,power density, COD removal and phenanthrene degradation rate were283.4mV,13.91mW/m2,39.4%and28.9%. Also, the anode and cathode internal resistances were closelyrelated to the phenanthrene concentration. The resistances of anode and cathode with0.5mg/Lphenanthrene were lowest with120.60Ω and23.22Ω. In contrast, the biomass andelectrochemical activity of the anode were highest.(3) The effect of Tween80on the electricity generation, the pollutant removal and internal resistance of the phenanthrene-SMFC system were also examined. With the increasein the phenanthrene concentration, the electricity generation and pollutant removal weresuppressed. With0.5mg/L phenanthrene, the peak cell voltage, power density, COD removaland phenanthrene degradation rate were226.3mV,10.00mW/m2,36.0%and22.2%.However, they were92.7mV、0.92mW/m2、18.3%and14.5%with10.0mg/L phenanthrene.