Improving the Electrochemical Properties of Electro-Dialysis Heterogeneous Cation Exchange Membrane by Surface Modification

Abstract

In this research, the surface modification of heterogeneous cation exchange membrane was carried out to achieve efficient electrochemical properties which are useful in applications such as electro-dialysis processes related to water recovery and water treatment. For the purpose, styrene butadiene rubber (SBR), multi walled carbon nano tube (MWCNT), activated carbon (AC), and sodium dodecyl sulphate (SDS) were used. A thin film of (SBR), (SBR-blend-MWCNTs), (SBR-blend-AC), and (SBR-blend-SDS) was applied as surface modifier on the virgin membrane surface using the casting technique. Scanning electron microscope (SEM) images indicated that the membrane surface modification results in filling of cracks and fissures with the modifier. Besides surface coating, the diffusion of the modifier into the membrane matrix occupies the voids, cavities, and fissures in the membrane matrix. The results revealed that the membrane potential, transport number, and selectivity, all are improved by the surface modification. (SBR-blend-SDS) coated membrane exhibited lower potential, transport number, and selectivity compared to other modified membranes. The SBR coating of the virgin membrane decreased the ionic permeability and flux which increased again by additive loading in the modifier solution. Conversely, membrane real electrical resistance showed an opposite trend. The (SBR-blend-AC) coated membrane showed better performance compared to the virgin type and other modified membranes.