Transport of Gold Ion from a Hydrochloric Acid Solution across a Supported Liquid Membrane Containing Sulfide Podand

Abstract

The transport of gold ions (5X105 M) from a diluted hydrochloric acid solution to a stripping solution across a supported liquid membrane (SLM) containing 0.1 M solution of polydentate neutral sulfide podand 1,12-di-2-thienyl-2,5,8,11-tetrathiadodecane (TTD) in m-chlorotoluene was studied. The rate of transport of gold ions increased in the sequence of the stripping solutions, NaBr<NH3, thiourea<NaSCN<NaI<thiosulfate.Among three microporous polymers used, the rate with Celgard 2500 membrane is ca. 23% higher than for Celgard 4510 or 2502. The present result shows that the selectivity for gold ion is good against copper, zinc and iron ions present in 200 :1 excess. The gold flux (J) increases almost linearly with an increase in the initial gold concentration over the range 10-5 -10.4 M; for 5X10-5 M Au it is equal to 10.3X 10.8 mol cm 2 h-1.