Reaction ability of heterochain complex-forming organopolymeric and organosilicon S-, N-containing sorbents toward noble metals

Abstract

Organopolymeric and organosilicon heterochain complex-forming sorbents containing aliphatic thioether or (and) weakly basic amino groups or the complex selective analytical groups are highly effective sorbents for selective recovery and concentration of noble metals. They are characterized by high values of distribution coefficients and sorption capacity for noble metals owing to high concentration of functional groups in the polymeric chain (Table 1, 2). The mechanism of sorption of some noble metals from hydrochloric (Pd (II), Pt (IV), Rh (III), Au(III)) and nitric (Pd (II), Ag (I)) solutions by heterochain sorbents of net, linear and cyclic structure is discussed. It was shown, that mechanism of the interaction of metals ions with functional groups of sorbents and the type of generated sorption complexes are defined by the nature of electron-donor atoms and the metal, by the structure of the functional groups and their state depending on the acidity of solution, by equilibrium of complexation and hydrolysis of complex metal forms in solution as well by the composition of solution. Selectivity and the rows of sorption affinity of S-; S,O- and S,N-containing sorbents are in agreement with the concept of hard and soft acids and bases.