Characterization and application of novel fly ash blended ceramic membrane in MFC for low-cost and sustainable wastewater treatment and power generation.

Abstract

Field-scale application of the microbial fuel cell (MFC) technology faces a major constraint due to the widely used high-cost proton exchange membrane Nafion, prompting lately, the development of ceramic membranes using different clay minerals. In the present study, the characteristics and applicability of a novel ceramic membrane fabricated using potter's clay (C) blended with varying proportions (0, 5, 10, and 20wt%) of fly ash (FA), designated as CFA0, CFA5, CFA10, and CFA20, were assessed for cost-effective and sustainable use in MFC. On assessing the properties of the membrane, CFA10 was found to exhibit superior quality with fine pore size distribution (average 0.49μm) favoring higher water uptake and less oxygen diffusion. The CFA10 membrane showed a maximum proton mass transfer coefficient (4.32 ± 0.04 × 10-5cm/s) that was about three times that of the control CFA0. The oxygen mass transfer coefficient of CFA10 was 5.13 ± 0.12 × 10-5cm/s, which was about 40% less than in the control. X-ray diffraction (XRD) analysis of CFAmembrane revealed the richness of quartz, which facilitates proton conductance and water retention. The CFA10 membrane fitted MFC demonstrated a peak power output of 4.57W/m3 (twice that in CFA0) with an average of 80.02 ± 0.86% COD removal and 68.03 ± 0.13% coulombic efficiency in a long-term study indicating its improved applicability and durability. Electrochemical kinetics involving cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) also affirmed the efficacy of CFA10 membrane in MFC showing peak current output of 13.95mA and low ohmic resistance (74.2 Ω). The novel (CFA10) ceramic membrane amalgamated with the coal fly ash, a waste of concern, shows promise for high MFC performance at a much reduced (98% less) cost that can be used for sustainable scale-up of the technology.