Development of cation exchange resin-polymer electrolyte membranes for microbial fuel cell application

A new class of composite membranes was made based on sulfonated poly ether ether ketone (SPEEK) incorporated with micron-sized sulfonate styrene-crosslinked divinyl benzene-based cation exchange resin particles as fillers with desired properties of higher ion exchange capacity, lower oxygen crossover, lesser mono, and divalent alkali cation transport for microbial fuel cell (MFC) applications. Such cation exchange resin-based composite membranes showed good membrane homogeneity as revealed from SEM images. XRD patterns showed better amorphous nature for the composite membranes with increase in resin loading. FT-IR spectra of composite membranes showed the presence of hydrogen bonding between the sulfonated PEEK and resin. The effects of existence of hydrogen bonding in the properties of membranes such as water uptake, transport of cations other than proton, oxygen crossover, and proton conductivity were discussed. The composite membranes showed one order lesser oxygen mass transfer coefficient (K-o) in the range of 10(-6) cm/s when compared to Nafion membranes. The composite membranes were tested in a single chamber Pt/C-coated air cathode MFC with Escherichia coli as anodic microbial inoculum. With resin, the SPEEK composite membranes showed higher power density value of 410 mW/m(2) for 7.5 % IER + SPEEK composite membrane compared to that of Nafion (47 mW/m(2)) and SPEEK (77 mW/m(2)) membranes with same configuration.