Removal of Chromium(VI) from Acidic Solutions using a Hybrid Liquid Membrane - Electrodialysis Process
A new hybrid process for chromium(VI) removal from aqueous solutions is presented. Transport through bulk liquid membranes was found to be effective for chromium(VI) anions removal from chloride acidic solutions during galvanostatic electrodialysis. Solutions of tri-n-octylamine (TOA) with admixtures of di(2-ethylhexyl)phosphoric acid (D2EHPA) in 1,2-dichloroethane were used as the liquid membranes. Effects of current density, chromium(VI) and hydrochloric acid concentration in the feed solution, carrier and admixture concentration in the liquid membrane, type of acid in the stripping solution were studied, and optimal conditions were determined. It is demonstrated that a practically complete removal of chromium(VI) from the feed solution containing 0.01 M K2Cr2O7 is achieved during 1.0 −4.0 h of electrodialysis. A maximum stripping degree of ~ 90 % is obtained under the optimal conditions. A possibility of effective single-stage removal of chromium(VI) into dilute solutions of hydrochloric, sulphuric, perchloric, phosphoric acids and water is demonstrated.
Date
04.01.2016.
Keywords
electrodialysis; chromium(VI); liquid membrane; facilitated transport; tri-n-octylamine
