Chlor–alkali electrolysis

Chlor–alkali electrolysis simultaneously produces two chemical products via electrolysis of sodium chloride solution (i.e., brine); namely, chlorine (Cl2) and sodium hydroxide (NaOH). These two primary products distinctly differ from each other in their chemical properties and are crucial fundamental materials for numerous industrial and social applications. In this chapter, first, the history of the chlor–alkali industry is briefly reviewed, followed by an overview of the three chlor–alkali technologies currently in use today; namely, mercury cells, diaphragm cells, and membrane cells. Then, because the global market share of membrane cells has grown significantly, this cell will be used as representative in the remaining sections: first, material and electrochemistry of the membrane cell; second, system configuration and operation; third, main industrial players, and task analysis for performance improvement; and fourth, gas diffusion electrode as a new concept for the cathode.