E. Lachowicz et al., SELECTIVE UP-HILL TRANSPORT OF GOLD TO IODIDE STRIPPING SOLUTION THROUGH A SOLVENT MODIFIED LIQUID MEMBRANE CONTAINING A POLYSULFIDE PODANDAS CARRIER, Analytica chimica acta, 327(2), 1996, pp. 175-181
The polydentate neutral sulphide podand 1,12-di-2-thienyl-2,5,8,11-tet
rathiadodecane (TTD), C4H3S-(CH2-S-CH2)(4)-C4H3S, which Shows high aff
inity towards ''soft metal ions'' has been used as a carrier for gold
transport through a supported liquid membrane (SLM). Transport of gold
(5x10(-5)M) from hydrochloric acid solution to the stripping solution
was facilitated by TTD in m-chlorotoluene(MCT)/kerosene solution immo
bilized in the pores of a polyvinylidene fluoride Millipore membrane.
A study of the influence of different chemical and physical parameters
on Au transport has been carried out. This includes the presence of k
erosene in TTD-MCT solutions, the concentration of the carrier in the
liquid membrane, the concentration of the stripping agent NaI (or NaSC
N) and the stirring rate of both aqueous solutions. The highest value
obtained for the permeability coefficient P was 0.34 cm min(-1), and f
or the Au flux 1.5 x 10(-6) mol m(-2) s(-1). A high selectivity in the
separation of Au from its bi-cation mixtures with an excess of Zn, Cu
(II), Fe(III), or Cd was achieved.