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

Abstract

The combined anaerobic-aerobic conditions in air-cathode single-chamber MFCs were used to completely mineralize pentachlorophenol (PCP; 5 mg/L), in the presence of acetate or glucose. Degradation rates of 0.140 ± 0.011 mg/L-h (acetate) and 0.117 ± 0.009 mg/L-h (glucose) were obtained with maximum power densities of 7.7 ± 1.1 W/m(3) (264 ± 39 W/m(2), acetate) and 5.1 ± 0.1 W/m(3) (175 ± 5 W/m(2), glucose). At a higher PCP concentration of 15 mg/L, PCP degradation rates increased to 0.171 ± 0.01 mg/L-h (acetate) and 0.159 ± 0.011 mg/L-h (glucose). However, power was inversely proportional to initial PCP concentration, with decreases of 0.255 W/mg PCP (acetate) and 0.184 W/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 ± 0.002 mg/L-h, acetate; 0.173 ± 0.005 mg/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 ± 0.01 mg/L-h, acetate; 0.172 ± 0.009 mg/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.

Efficient In Situ Utilization of Caustic for Sequential Recovery and Separation of Sn, Fe, and Cu in Microbial Fuel Cells

“…These lower metal recoveries were consistent with less increase in effluent pH (Figure S2B), lower currents (Figure S2C), and more negative cathode potentials of the MFC Sn and MFC Fe (Figure S2D). The combination of Cu(II) reduction and oxygen reduction resulted in higher currents (Figure S2C), implying the contribution of the binary electron sinks of oxygen and Cu(II) present in the catholyte of the MFC Cu to higher currents, consistent with previous reports in the co‐presence of oxygen and either pentachlorophenol, Cu(II) or Co(II) ,,. The presence of multiple electron acceptors in the catholyte of MFCs provides more electron sinks for cathodic electrons and resulted in higher currents ,…”

“…Power was calculated based on the voltage drop across the external resistor, measured with a data acquisition system (PFN‐2042 PROFINET, Hongge, Taiwan), as P = I U , where I =current, and U =voltage. Power density was normalized to the projected surface area of the separator, allowing comparison of the results to previous results ,. CE was calculated as the ratio of the total coulombs calculated by integrating the current over time, and the theoretical amount of coulombs available based on the COD removed in the anodes of MFCs …”

Effective factors on the performance of microbial fuel cells in wastewater treatment – a review

“…[104] Hydrocarbon-contaminated sediments, [105] benzene-and ammonium-contaminated groundwater, [106] diesel range organic hydrocarbons, [104] nitroaromatic compounds, [107] chloroethane, pyridine, alkanes, indole, phenol and pentachlorophenol have been treated by MFCs. [108][109][110] The amount of electricity generated by each substrate depends on the MFC construction and other parameters which cannot be compared.…”

Correlation between circuital current, Cu(II) reduction and cellular electron transfer in EAB isolated from Cu(II)-reduced biocathodes of microbial fuel cells

“…The anodes were inoculated with suspended bacteria collected from a previous acetate-fed MFC reactor and an equivalent volume of nutrient solution containing acetate (1.0 g/L) was added [30][31]. The cathodes were fed using the same medium, except acetate was replaced by NaHCO 3 (10 mg/L), with further addition of Cu(II) (5 mg/L) to the cathodic chambers.…”