Ion-exchange membranes in electrolysis process

Ion-exchange membranes (IEMs) have been used in many applications in electromembrane processes that can be used to treat saline water and wastewater, synthesize chemicals such as hydrogen and organic and inorganic acids, and produce energy in many industries. Although IEMs in electromembrane processes are well documented in the literature, the application of IEMs in electrolysis reactors is still a developing subject. The IEMs are classified into three main groups: Anion-exchange, cation-exchange, and bipolar membrane. The anion-exchange and cation-exchange membranes can transfer anions and cations while bipolar membranes dissociate water into H+ and OH− ions under the applied electrical field. The transferred ions affect the pH of the electrolyte solutions, so the hydrogen evolution reaction and oxygen evolution reaction differ by changing the energy consumption of the electrolysis process. This chapter examines the applications of IEMs in the electrolysis process and their effects on system efficiencies.