Statistical optimization of pentachlorophenol biodegradation and electricity generation simultaneously in mediator – less air cathode microbial fuel cell
Microbial fuel cell (MFC) presents a novel method for simultaneous bioelectricity generation and pollutants treatment. In this study highly resistant and toxic pentachlorophenol (PCP) has been degraded as substrate in mediator – less air cathode MFC, to generate bioelectricity. Response surface methodology (RSM) based on central composite rotatable design (CCRD) was applied to determine the optimum condition for PCP degradation, power density and coulombic efficiency. Three operating variables, namely PCP – glucose concentration (mg/L), temperature (оC) and pH, with a total of 15 individual experiments were conducted to optimize the combination effects of the variables. The predicted optimum conditions was 70-2500mg/L, 20 оC and 7.5 for PCP – glucose concentration (mg/L), temperature (оC) and pH, respectively, resulting increasing PCP degradation from 58 to 73%, by rate 125%, power density from 7.84 to 23.08W/m2, by rate 294%, and coulombic efficiency from 39 to 49% by rate 126%. RSM based upon CCRD can be applied to correlate the statistical optimization results, with regression coefficients of 96.57, 94.95 and 96.4 for the PCP degradation, power density and coulombic efficiency, respectively. This proved that the RSM based on CCRD is efficiently applicable for statistical optimization of PCP biodegradation and electricity generation simultaneously in MFC. Dominant bacteria most similar to the anaerobic Desulfobacterium aniline, Actinomycetes and Streptacidiphilus, Rhodococcus erythropolis, Amycolatopsis and Gordonia were found on the anodic biofilm. These results demonstrate efficient degradation of PCP in MFC.