Reduction in particle size of vermiculite and production of the low-cost earthen membrane to achieve enhancement in the microbial fuel cell performance

A membrane used in the microbial fuel cell is one of the most crucial components. It sums up to half the cost of the whole assembled MFC. The novel earthen membrane has been prepared in this study using reduced particle size of vermiculite to give a low-cost alternative to the commercial Nafion 117 membrane. The M5 membrane prepared using red soil, montmorillonite and vermiculite (nano-milled for 5 hr) have outperformed all other fabricated membranes. The reduction in particle size of vermiculite in the earthen membrane has shown better proton diffusion and reduced oxygen mass transfer into the anode. The ion exchange capacity of the membrane has also been improved. The MFC (R5) containing the M5 membrane has yielded the highest COD removal ef-ficiency (88.06 +/- 0.9%) and the highest coulombic efficiency (19.4 +/- 0.67%). The power density achieved by R5 was 995.73 +/- 49.3 mW/m3 which is the highest among all the installed microbial fuel cells and is 8.4 folds higher than the control. The study sums up that the M5 membrane can be utilized as a novel and cost-effective alternative to the commercial Nafion membrane.