Transport of cadmium ions through a liquid membrane containing amine extractants as carriers

The comparison of the transport rates of Cd(II) from an aqueous feed chlori de solution to an ammonium acetate strip solution through a bulk liquid mem brane (BLM) consisting of tri-n-octylamine (TNOA) or tricapryl amine (N-235 ) as carriers in carbon tetrachloride solution was made. The influence of c arrier concentration in the membrane, H+ and I- concentrations in the feed phase, and ammonium acetate concentration in the stripping phase was invest igated. The optimal conditions for the transport of Cd(II) ions have been f ound. It is demonstrated that the transport of Cd(II) is coupled by co-tran sport flow of protons. The apparent extraction activation energies were fou nd to be 4.5 kJ mol(-1) for TNOA and 6.8 kJ mol(-1) for N-235. respectively . The membrane permeability (P) of Cd(II) through a supported liquid membra ne (SLM) was determined. The experiments show that TNOA carrier is better t han N-235 in transport efficiency for Cd(II). (C) 2000 Elsevier Science B.V . All rights reserved.