Properties and structure of heterogeneous ion-exchange membranes after exposure to chemical agents

Abstract

This work deals with resistance of ion-exchange membranes in selected chemical solutions. Specimens of heterogeneous membranes were analyzed after exposure to chemically aggressive agents such as nitric acid, sodium hydroxide, etc. The analyses were carried out after period up to 6 months. The chemical resistance was evaluated from the mechanical and electrochemical property changes’ point of view before and after exposure. The tested materials were not only the membranes themselves but also their individual components, i.e., ion-exchange resins from various manufacturers and polyester reinforcing fabrics. The results show that exposure to NaOH solution has the most damaging effect especially on reinforcing fabric and a membrane as whole due mainly to dimension changes. The same stands for electrochemical resistance of the membrane and permselectivity. Ion-exchange capacity remains almost the same after exposure.