Study of sorption of platinum metals, gold and silver by phosphonium hydroxide antonite

The aim of the work was to study and to use a phosphonium hydroxide anionite for concentrating of trace amounts of platinum metals, gold and silver from the mixed solutions composed of copper, nickel, cobalt, iron and zinc. The experiments were done using radionuclides of determined and interfered elements. Conditions for sorption concentrating of the noble metals by phosphonium hydroxide were determined by the selectivity of the phosphonium hydroxide to the noble metals from acid solutions. A noble metal sorption degree was observed from the experiments to be rather high at the acid concentration level of 0.1-0.5 M. At higher than 0.5 M acid concentration sorption activity decreased. With increase of chlorine acid-concentration sorption of palladium was observed to considerably decrease, while iridium sorption was increased. The latter fact can be caused by lowering of hydration of iridium ions. A considerable decrease of capability of the noble metal sorption from nitric acid solutions was observed. It is possible that HNO3 anions are strongly bound with the anionite functional group. Thus, nitric acid reduces sorption of the noble metals in the following order: Ir>Ru>Pd>Pt>Os, and it does not have effect on the sorption activity of Au and Ag. Increase of H2SO4 concentration in the solution has slightly reduced noble metal sorption activity. Copper, nickel, iron and other metals accompanying the noble metals, at concentration ratio of 1:1000 have resulted in decrease of sorption activity of the noble metals, although sorption of iridium was increased in the presence of copper, silver and nickel. We suggest that copper, silver and nickel have formed the complex functional compounds, which can probably undergo an anion exchange