DEVELOPMENT OF MINIATURIZED MICROBIAL FUEL CELL FOR ELECTRICITY GENERATION FROM WASTE

Abstract

Microbial fuel cells (MFCs) are known to convert chemical energy stored in organic matter to electrical energy by microbial electrochemical reactions. The present studies deal with the fabrication of two types of MFCs viz. H-shaped and miniaturized MFCs using low cost materials. H-shaped MFC shown open circuit voltage (OCV) of 750 mV after 42 days while miniaturized MFC depicted OCV of 671.2 mV only after 15 hrs. Aluminium sheet (Al) coated with graphite paste (G), polyaniline (PANI), reduced graphene oxide (rGO) were used as electrode materials while agar gel was employed as proton exchange material. Comparison of different electrode materials (G/Al, rGo/G/Al, PANI/rGO/G/Al) was evaluated using cyclic voltammetry, four points probe conductivity and scanning electron microscopy (SEM). rGo/Graphite paste/Al was found the most appropriate electrode material with conductivity of 0.52 S/m, addition of rGO enhanced the conductivity upto 19.40 % to that of G /Al. Fermenting bacteria present in kitchen waste (potato slurry) were used in anode chamber as a main source for electricity generation. Furthermore, effect of adding real saliva, artificial saliva to anolyte and salivary enzymes (lysozyme and α-amylase) immobilization on anode surface were also observed. Instantaneous enhancement of potential was attained after adding saliva. Similar results were obtained when study was conducted with the electrodes having immobilized salivary enzymes while no substantial increase in current was observed when only artificial saliva was used. Thus, miniaturized MFC developed using 2 rGO/G/Al as electrode material and natural saliva as supplement to anolyte gave OCV of 671.2 mV, maximum current of 53 μA across 10 kΩ load and internal resistance of 1042.35 Ω with a shelf life of 40 days. Thus, assembly of 3 to 4 such miniaturized MFCs could able to generate electricity required for biosensors and light emitting devices (LEDs). Keywords: MFC, PANI, rGO, Anolyte.