Bioelectricity production from municipal leachate in a microbial fuel cell: Effect of two cathodic catalysts

Abstract

The objective of this work was to evaluate the effect of the cathodic catalyst (either chalcogenide or Pt) on bioelectricity production from actual municipal leachate in a microbial fuel cell equipped with an anode made of granular graphite (MFC-G) and seeded with an inoculum enriched in Mn(IV)-reducing bacteria.Each face (I and II) of the MFC-G was characterized by separate (I and II), in series, and parallel connection. Parallel connection of faces increased the maximum volumetric power up to 1239 and 1799 mW m−3 for RuxMoySez and Pt, respectively. In general parallel connection of electrode faces significantly decreased the Rint (44 and 77 Ω for RuxMoySez and Pt, respectively). In the batch operation where the cells were connected to external resistances (Rext) the average volumetric powers PV-ave in the second cycle of batch operation were 1005 ± 5 and 1317 ± 687 mW m−3 whereas organic matter removal efficiencies of 70 and 85% were registered for the RuxMoySez and Pt, respectively. During the repetitive batch operation of the cells loaded with an actual leachate there was preliminary evidence of an in-cell enrichment process. In principle, the MFC with catalyst RuxMoySez exhibited a performance 24% and 20% lower than that with Pt (on PV-ave and organic matter removal basis, respectively). This would point to a trade-off or compromise solution, since the cost of RuxMoySez catalyst is 70% lower than that of Pt.