Optimisation of Electrode Spacing in Cow Dung-Fed Microbial Fuel Cell for Enhanced and Sustained Electricity Generation

Y. Thiagarajan, R. Ashok Kumar and T.S. Sivakumaran

This paper is dealt with conduct of experiments in Microbial fuel cell to find optimum electrode spacing for enhanced and sustained electricity generation. Besides, cow-dung fed MFCs is not subjected to cyclic-voltametric studies to evaluate their efficiency so far. Therefore, cyclic-voltametric study is also included for the first time in cow dung fed MFC. Two polycarbonate containers (500ml) one with 8cm (MFC-I) and another with 8cm (MFC-II) electrode spacing are fabricated and executed. 2% KMnO4 is used as catholyte and graphite material as electrodes. Experiment is conducted for 30days. Interestingly in a 30 days cycle, MFC-II generated a maximum voltage 1.3V on 18th day. Secondly, the reactor generated a sustained voltage of 1.0V and above for a period of 25 days continuously from 6th day to 29th day and exhibited better performance than MFC-I. On comparing, there was 18% increase in output voltage; 18% and 20% increase in current and current density respectively; 43% and 48% increase in power and power density respectively in MFC-II. Voltagram obtained for both reactors were fitted with US-convention model and analysed. MFC-II exhibited better reduction-oxidation reactions and showed one peak at +0.8V in the reduction phase without any interruption; redox coupling is almost symmetrical. Therefore, it is demonstrated that 4 cm (MFC-II) electrode spacing is ideal for harvesting sustained electricity.

Volume 11 | 01-Special Issue

Pages: 205-213