Transport of Au(CN)2− across a supported liquid membrane using mixtures of amine Primene JMT and phosphine oxide Cyanex 923

The transport of Au(CN)2− between aqueous solutions and organic phases of the mixture of the amine Primene JMT and the phosphine oxide Cyanex 923 in xylene was studied under various experimental conditions, i.e., extractant mixtures and gold concentrations. The behaviour of the system with different organic diluents, aqueous ionic strength and the selectivity of the system with respect to the transport of different metal–cyano complexes were also investigated. The transport of gold(I) can be ascribed to a mechanism which consists of (i) a diffusion process through the feed aqueous diffusion layer, (ii) a fast interfacial chemical reaction and (iii) a diffusion of HAu(CN)2RL and HAu(CN)2RL2 (R=the amine, L=the phosphine oxide) through the membrane.