Simultaneous generation of electricity and removal of organic load from synthetic wastewater in a membrane less microbial fuel cell: Parametric evaluation

Abstract

This work deals with the simultaneous generation of electricity and removal of organic load from synthetic wastewater containing eqimolar concentration of glucose and glutamic acid. The effect of initial COD (mg/L), anodic pH and metals (Zn2+, Cr6+, and Fe3+) concentration on the generation of current density and voltage has been studied. Although, the amount of COD removed increases with increase in the initial COD value from 500 to 2500 mg/L, the maximum generation of current density (19 mA/m2) and voltage (14.8 mV), after 7 days of operation, is achieved at the initial COD value of 1500 mg/L at anodic pH value of 7. Difference in the anodic and cathodic pH has also been observed maximum (∼1) at the initial COD value of 1500 mg/L. Addition of metals initially increases the voltage and power density generation, attains a maximum value at a certain metal concentration and decreases thereafter with increase in metal concentration. Optimum concentration of metals, that is, 8 mg/L Zn2+, 7 mg/L Cr6+, and 10 mg/L Fe3+ in the solution produces maximum voltage of 142, 490, and 321 mV, after 7 days of operation, respectively. Corresponding maximum power densities are 6.9, 508, and 192 mW/m2, respectively. The present process seems to have maximum current density and voltage generation capacity in comparison to some recently reported literatures on membrane less MFCand is able to reduce COD value below permissible limit with the initial COD value ≤1250 mg/L. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 255–264, 2015