The Effect of Electrode Spacing and Size on the Performance of Soil Microbial Fuel Cells (SMFC)

Abstract

Soil microbial fuel cells (SMFC) have gained a great attention as an eco-friendly technology that can simultaneously generate electricity and treat organic pollutants from the contaminated soil. We evaluated the effect of electrode spacing and size on the performance of SMFC treating soil contaminated with organic pollutants. Maximum power density decreased with increase in electrode distance or decrease in electrode size, likely due to higher internal resistance. The maximum voltage and power density decreased from 326 mV and 19.5 m W / m 2 with 4 cm of electrode distance to 222 mV and 5.9 m W / m 2 with 9 cm of electrode distance. In case of electrode size test, the maximum voltage and power density generated was 291 mV, 0.34 m W / m 3 when both of anode and cathode area were 64 c m 2 with 4 cm of electrode distance. The maximum voltage decreased by 19~29% when the anode area decreased to 16 c m 2 while only 3~12% of voltage decreased with cathode area decrease. The maximum power density decreased by 49~68% with decreasing anode size, and by 29~47% with decreasing cathode size. These results showed that the anode area had more significant effects than the cathode area on the power generation of SMFC which has a high internal resistance due to a coexistence of soil and wastewater in the reactor.