Facilitated separation of Fe(III) from Fe(III)/Cu(II) solutions with supported liquid membranes. Liquid-liquid extraction experiments.

The extraction of Fe~III from an aqueous solutio n containing Fe~III and Cu~II is reported in this paper. The aqueous p hase was Fe~III and Cu~II in H_2SO_4 solution. The solvent was n-de canol containing D2EHPA which was employed to facilitate the extraction of Fe~ III from Cu~II. The effects of the acid concentration in the aqueous ph ase and the carrier concentration in the organic phase were studied. The liquid- liquid extraction experiments showed that the reaction of Fe~III and D2EHPA at the interface between the aqueous and the organic phase was much faster than that of Cu~II and D2EHPA. The diffusion velocity of the Fe~III comple x was much slower than its complexation rate with D2EHPA at the aqueous-o rganic interface. However the reaction of Cu~II with D2EHPA at the interfac e was much slower than the complex diffusion velocity. The pH of the aqueous sol ution and the D2EHPA concentration have a very important influence on the extrac tion ratios of the ions.