Investigation of rhamnolipid addition on the microbial fuel cell performance and heavy metal capture in metal laden wastewater

Abstract

Wastewater loaded with metals was investigated in this study for their remediation, it was used a dual chamber microbial fuel cell aided with rhamnolipid biosurfactant at 100 mg/L and 500 mg/L in the anode and inoculated with Shewanella oneidensis MR-1, and K3Fe(CN)6 50 mM in 100 mM of phosphate buffer solution was used in the cathode chamber. The bacteria demonstrated a higher specific growth rate of 0.11 h−1 and better biofilm formation analyzed by the SEM. The highest power density was 13.9 mW/m2 determined at 100 mg/L of rhamnolipid. Furthermore, the internal resistance for the same concentration was 2.8 Ω, which indicates the low resistance of electrons through the external circuit. Metal removal had the highest removal of 60.2 %, 89.5 %, 83.9 %, 90.6 %, and 47.9 % for Cu, Mg, Mn, Zn, and Na, respectively, corresponding to the wastewater coupled with rhamnolipid at concentration of 500 mg/L. Furthermore, COD removal was 28.7 % and 17.0 % for biosurfactant concentrations of 100 mg/L and 500 mg/L, respectively. These results demonstrated the high efficiency of microbial fuel cells with wastewater loaded with rhamnolipid.