Effect of different anions on separation of cadmium and zinc by supported liquid membrane using TOPS-99 as mobile carrier

Abstract

In this present work, the effect of different anions such as Cl −, NO 3 −, SO 4 2−, CH 3COO −, SCN − and ClO 3 − on separation of cadmium and zinc by supported liquid membrane using TOPS-99 as mobile carrier was studied. Celgard 2400, a micro-porous poly-propylene film was used as the solid support for the liquid membrane. It was observed that, in the presence of 10 mol/m 3 of NaCl, NaNO 3, Na 2SO 4, CH 3COONa, NaSCN and NaClO 3 of added salt solutions in feed, the zinc flux J Zn, decreased, but cadmium flux J Cd remained constant at 0.125 × 10 −6 mol/m 2 s. In the presence of NaCl and NaNO 3 anions the highest flux for zinc obtained were 8.40 × 10 −6 and 5.06 × 10 −6 mol/m 2 s, respectively, with 500 mol/m 3 of added salt solution. In the presence of NaSCN, CH 3COONa and NaClO 3 salts the highest flux obtained for zinc were 6.58 × 10 −6, 6.00 × 10 −6 and 3.00 × 10 −6 mol/m 2 s, respectively, with 100 mol/m 3 of added salt solution in feed. But in presence of Na 2SO 4 salt the highest flux for zinc was 4.30 × 10 −6 mol/m 2 s with 50 mol/m 3 of added salt solution in the feed. At pH 2.25 the co-permeation of cadmium with zinc was negligible, so the highest separation factor was obtained at this pH. The maximum separation factors obtained in the presence of NaCl, NaNO 3, Na 2SO 4, CH 3COONa, NaClO 3 and NaSCN salt solutions were 39.04, 23.55, 20.02, 27.89, 13.94 and 30.61, respectively.