Performance assessment of partially sulfonated PVdF-co-HFP as polymer electrolyte membranes in single chambered microbial fuel cells

Abstract

In the present study, PVdF-co-HFP copolymer and its sulfonated derivatives have been analyzed as polymer electrolyte membrane in single chamber MFCs. The sulfonation of PVdF-co-HFP copolymer was performed by treating with chlorosulfonic acid for 5, 7 and 9h, resulting in 23%, 30%, and 18% of degree of sulfonation (DS) in the respective SP-5, SP-7, and SP-9 membranes. On observing the membranes under field emission scanning electron microscope fitted with EDAX, porosity was found to be increasing with increase in the duration of sulfonation except for 9h duration. The elemental analysis of the membranes indicated the presence of higher sulfur and oxygen content with the increasing sulfonation duration except for 9h duration, for which crosslinks were formed via sulfone linkages. The membranes were characterized for their ion exchange capacity (IEC) and proton conductivity; IEC value of 0.21meqg-1, 0.42meqg-1, and 0.12meqg-1 and proton conductivity of 0.0012Scm-1, 0.00363Scm-1, and 0.0006Scm-1 were observed for SP-5, SP-7, and SP-9 membranes. Open air cathode MFCs with membrane electrode assemblies (MEA) containing sulfonated and non-sulfonated PVdF-co-HFP membranes have been analyzed for their overall MFC performance. It was observed that amongst these membranes, MFC with SP-7 membrane showed the maximum power and current density of 290.176±15mWm-2 and 1390.866±70mAm-2 with an overall ~89% COD removal in 28days operation, using electrogenic mixed firmicute consortium. In overall, the study illustrates the impression of sulfonated PVdF-co-HFP membranes as PEM and its application in MFC for harvesting bio-energy. © 2014 Elsevier Ltd.