Mineralization of pentachlorophenol with enhanced degradation and power generation from air cathode microbial fuel cells

The combined anaerobic-aerobic conditions in air-cathode single-chamber MFCs were used to completely mineralize pentachlorophenol (PCP; 5mg/L), in the presence of acetate or glucose. Degradation rates of 0.140±0.011mg/L-h (acetate) and 0.117±0.009mg/L-h (glucose) were obtained with maximum power densities of 7.7±1.1W/m³ (264±39W/m², acetate) and 5.1±0.1W/m³ (175±5W/m², glucose). At a higher PCP concentration of 15mg/L, PCP degradation rates increased to 0.171±0.01mg/L-h (acetate) and 0.159±0.011mg/L-h (glucose). However, power was inversely proportional to initial PCP concentration, with decreases of 0.255W/mg PCP (acetate) and 0.184W/mg PCP (glucose). High pH (9.0, acetate; 8.0, glucose) was beneficial to exoelectrogenic activities and power generation, whereas an acidic pH=5.0 decreased power but increased PCP degradation rates (0.195±0.002mg/L-h, acetate; 0.173±0.005mg/L-h, glucose). Increasing temperature from 22 to 35°C enhanced power production by 37% (glucose) to 70% (acetate), and PCP degradation rates (0.188±0.01mg/L-h, acetate; 0.172±0.009mg/L-h, glucose). Dominant exoelectrogens of Pseudomonas (acetate) and Klebsiella (glucose) were identified in the biofilms. These results demonstrate that PCP degradation using air-cathode single-chamber MFCs may be a promising process for remediation of water contaminated with PCP as well as for power generation.