Effect of zeolite on SPEEK /zeolite hybrid membrane as electrolyte for microbial fuel cell applications

Abstract

A zeolite (H-faujasite) incorporated SPEEK membrane was demonstrated as an effective proton exchange membrane for Microbial Fuel Cell (MFC) application. The proton conductive faujasite zeolite contains uniform channels with an effective diameter ∼0.74 nm that permits small ions but restricts large hydrated ions. In this work, SPEEK/zeolite membranes were prepared by a solvent evaporation method with different weight percentages (2.5%, 5%, 7.5%, 10%) of zeolite. The physico-chemical properties of the composite membranes such as water uptake, ion-exchange capacity, proton conductivity, dissolved oxygen crossover and transport of cations were studied for their suitability in MFC. A maximum proton conductivity of 0.178 × 10⁻² S cm⁻¹ was obtained for 7.5% zeolite + SPEEK. All the membranes were tested in a Single Chamber MFC (SCMFC) using E. coli inoculum and Pt/C as cathode catalyst. The 7.5% zeolite + SPEEK membrane showed the highest power density (176 mW m⁻²) compared to that of commercial Nafion and other composite membranes.