Treatment of ethanolamine using an Fe(III)-based, two-chamber microbial fuel cell with continuous Fe(II) oxidation at the air cathode

Abstract

BACKGROUNDThe objective of this study was to investigate the feasibility of developing an integrated bio-electrochemical system for the removal of ethanolamine from wastewater by combining an Fe(III)-based microbial fuel cell (MFC) with a continuous Fe(II) oxidation system for simultaneous oxidation and reduction of iron in the same compartment. The ethanolamine in the Fe(III)-based MFC can be effectively converted to electrical energy by using the catalytic activity of microorganisms. In this respect, the authors investigated whether the introduction of a system for Fe(III) regeneration could enhance the sustainability of both power generation and the removal of ethanolamine in this integrated system. RESULTSThe experimental results obtained with a traditional Fe(III)-based MFC, operated with a ferric sulfate solution of 25 or 50 mmol L-1 Fe(III) mixed with ethylenediaminetetraacetic acid (EDTA) solution of 10 mmol L-1, showed that increasing the Fe(III) concentration leads to improved performance of the MFC; the maximum power density, open circle voltage (OCV), and Coulombic efficiency (CE) were all improved. However, the effluents from the cathode chamber contained a low concentration of Fe(III) due to deficient regeneration of Fe(III). In the integrated bio-electrochemical system developed in this work (enhanced Fe(III)-based MFC), the generated Fe(II) was oxidized at the air cathode via favorable oxygen diffusion and a Fe(II)-based fuel cell (FC). CONCLUSIONElectricity was sustainably generated from the enhanced MFC with 25 mmol L-1 Fe(III); the highest performance, in terms of maximum power density, OCV and CE, was achieved using 50 mmol L-1 Fe(III), thus indicating the increased efficiency of this integrated system. (c) 2015 Society of Chemical Industry