One-through selective separation of copper, chromium and zinc ions by hollow fiber supported liquid membrane

Abstract

The separation of a mixture of Cu(II), Cr(VI) and Zn(II) simultaneously from a sulfate media using two consecutive hollow fiber microporous liquid membrane extraction systems has been studied. The experiments were made in the one-through mode. LIX84-I and Aliquat336 were used as carrier extractants for copper and chromium in the first and second hollow fiber modules, respectively. Pure copper and pure chromium ions are extracted and stripped from first and second hollow fiber modules, respectively, but zinc ions cannot be extracted by both extractants due to pH conditions used in this study and remain in the raffinate. Results indicate that the percentage of extraction is highly dependent on pH of the feed solution and the pH value is 2.5 for the maximum extraction. The percentage of extraction of copper and chromium ions is enhanced when the concentration of LIX84-I and Aliquat336 is increased of which both maximum value is 0.5 M, and these results also occur in stripping phase. The influence of sulfuric acid and sodium hydroxide concentration in strip solution of each column was examined, and it was found that the percentage of extraction and stripping is further increased due to the difference of driving force. The maximum percentage of extraction for copper is 33% and 92% for chromium. The experimental results indicated the feasibility of separation and recovery of these metals from the dilute solution by using membrane technology