Extraction behavior of Cr(VI) and coexistence with interfering ions by trialkylamine

Solvent extraction of chromium(VI) with trialkylamine (N235) using kerosene/n-heptane as the diluent was investigated. The basic conditions for Cr(VI) extraction have been explored, and the influence of coexisting contaminants on extraction has been evaluated. The results indicated that the separation of Cr(VI) could be realized with N235, and the recovery rate could be increased by adding organophosphorus-tributyl phosphate as the modifier due to the strong bonding force of synergistic extraction. However, the inorganic phosphorus could inhibit the chemical reaction between tertiary amine and Cr(VI) ions owning to the competition of the limited adsorption sites. Besides, inorganic anions such as massive SO42− and NO3− could inhibit extraction of metal ions because of competition coordination. In addition, the separation of Cr(VI) from coexisting metal ions could be achieved with trialkylamine except Fe2+ due to its reducibility. Based on the results, the feasibility of pseudo-emulsion based hollow fiber strip dispersion used for separation and recovery of Cr(VI) has been evaluated, and the transport properties of Cr(VI) and coexistence with interfering ions have been explored.