Electricity Production Performance of Single- and Dual-cathode Microbial Fuel Cells Coupled to Carbon Source and Nitrate

Microbial fuel cells (MFC), devices that use bacteria as a catalyst to generate electricity, can utilize a variety of organic wastes as electron donors. The current generated may differ depending on the organic matter concentrations used, when other conditions, such as oxidant supply, proton transfer, internal resistance and so on, are not limiting factors. In these studies, a single-cathode type MFC (SCMFC) and dual-cathode type MFC (DCMFC) were used to ascertain the current's improvement through an increase in the contact area between the anode and the cathode compartments, because the cathode reaction is one of the most serious limiting factors in an MFC. Also an MFC was conducted to explore whether an improvement in electricity generation resulted from oxidizing the carbon sources and nitrates. About 250 mg $L^{-1}$ sodium acetate was fed to an anode compartment with a flow rate of 0.326 mL $min^{-1}$ by continuous mode. The current generated from the DCMFC was higher than the value produced from MFC with a single cathode. COD removal of dual-cathode MFC was also higher than that of single-cathode MFC. The nitrate didn't affect current generation at 2 mM, but when 4 and 8 mM nitrate was supplied, the current in the single-cathode and dual-cathode MFC was decreased by 98% from $5.97{\pm}0.13$ to $0.23{\pm}0.03$ mA and $8.40{\pm}0.23$ to $0.20{\pm}0.01$ mA, respectively. These results demonstrate that increasing of contact area of the anode and cathode can raise current generation by an improvement in the cathode reaction.

Single-cathode와 Dual-cathode 미생물연료전지의 탄소원과 질산성질소의 전류발생 특성

이 연구에서는 일반적인 음극부 한 개에 양극부 한 개로 구성된 single-cathode 미생물연료전지(SCMFC)와 음극부 한 개에 양극부 두 개로 이루어진 dual-cathode 미생물연료전지(DCMFC)를 이용하여 전류발생에 비치는 영향을 확인하였다. 이 결과 dual-cathode 미생물연료전지에서 single-cathode 미생물연료전지 보다 전류발생이 약 40% 높았으며 COD 제거율도 약 13% 더 높은 것으로 확인되었다. 이것은 양극부와 음극부의 접촉면적이 증가하여 양극반응속도가 향상된 것에 의한 것으로 판단되며 dual-cathode 미생물연료전지가 single-cathode보다 전류발생과 COD제거 측면서 더 효율이 높은것으로 나타났다. 음극부 전자수용체에 대한 영향 실험에서는 전자수용체로 사용된 질산성질소의 농도가 높아질수록 급격히 전류발생이 감소하는 것을 확인 할 수 있었으며, 이에 대한 적절한 처리가 필요한 것으로 나타났다.