Diffusive permeability of hybrid cation-exchange membranes MF-4SC/halloysite nanotubes

Abstract

The diffusion permeability through new hybrid materials based on a Nafion-type membrane (MF-4SC) and nanotubes of halloysite is investigated using the Nernst-Planck approach. A method of quantitative evaluation of physicochemical parameters (averaged and individual diffusion coefficients and averaged distribution coefficients of ion pairs in the membrane) of system ‘electrolyte solution - ion-exchange membrane - water’, which was proposed earlier, is further developed. The parameters of hybrid membranes on the base of MF-4SC and nanotubes of halloysite (5%wt. and 8%wt.) are obtained from experimental data on diffusion permeability of NaCl solutions using theoretical calculations. New model of three-layer membrane system can be used for refining calculated results with taking into account both diffusive layers. It is shown that adding of halloysite nanotubes into the membrane volume noticeably affects exchange capacity as well as structural and transport characteristics of original perfluorinated membranes. Hybrid membranes on the base of MF-4SC and halloysite nanotubes can be used in fuel cells and catalysis.