Selective electrodialysis process for the separation of potassium: Transmembrane transport of ions in multicomponent solution systems.

Selective Electrodialysis Process for the Separation of Potassium: Transmembrane Transport of Ions in Multicomponent Solution Systems. [Display omitted] • Monovalent selective electrodialysis was applied to separate KCl from bittern. • SO 4 2 - inhibits the migration of Mg2+. • The decrease of ionic strength will improve the separation performance of K+. • 74.83% of K+ could be recovered with the K+/Mg2+ permselectivity more than 7.72. With the development of global agriculture, the demand for potash is growing rapidly. The concentration of K+ in bittern can reach 10 g/L, but the economic benefit of existing extraction methods is still a key concern, and a new extraction method is urgently needed. The monovalent selective electrodialysis was proposed in this study to purify K+. The effects of coexisting ion concentration, voltage, temperature, and ionic strength of dilute solution on the separation of K+ from brine were investigated in ternary system, quaternary system, and quinary system, respectively. Monovalent selective electrodialysis was preliminarily applied to separate K+ from actual bittern. The results showed that monovalent selective electrodialysis can effectively extract K+ and reduce the ratio of Mg2+/K+ from 7.11 to 0.92 with a K+ recovery rate of 74.83%. [ABSTRACT FROM AUTHOR]