A physicochemical study of the sorption of lead: Correlations in a series of chelating polymer sorbents

The sorption properties of chelating polymer sorbents (CPSs), the derivatives of poly(styrene-2-oxy-azo-2′-oxybenzene), with respect to the lead ion are studied. The parameters of the sorption processes—optimum conditions of sorption (acidity, temperature, and time), the sorption capacities of sorbents, the possibility of desorption, and the stability constants of the chelated polymers—are determined. Quantitative correlations between p K′_OH of the functional analytical group (FAG) of the sorbent and σ _{o + p(p)} for ortho-and para-substituents, between p K′_OH and pH₅₀ for the formation of chelate complexes of lead, between p K′_OH and the stability of lead complexes (logβ), and between σ _{o + p(p)} and pH₅₀ for the formation of chelate complexes of lead are established with the aim of studying regularities of the influence of the structure and acid-base properties of FAGs on parameters of chemisorption of Pb²⁺. It is shown that the established correlations provide a means for quantitatively predicting physicochemical parameters of sorbents and the process of sorption of lead with the aim of targeted synthesis of CPSs and their use in the chemistry of polymer compounds and in the process of concentrating.