Influence of the Proportion and Type of Functional Groups on the Selective Properties of Modified Poly-3-Aminopropylsesquioxanes Toward Silver(i)

The effect of the proportion and type of functional groups on the selective properties of modified poly(3-aminopropylsilsesquioxanes) in silver(I) extraction from multicomponent aqueous solutions was studied. The sorbents were obtained by modifying poly(3-aminopropylsilsesquioxane) with sulfur-containing reagents at different temperature conditions, which allowed varying the ratio of monosubstituted and disubstituted thiourea groups, as well as amino groups. The sorbent structure was determined by IR spectroscopy and elemental analysis. It was found that an increase in the proportion of monosubstituted thiourea groups (from 40 to 75%) in the sorbent structure led to an increase in the degree of extraction and selectivity with respect to silver(I) in the pH range of 1–4. The introduction of an additional heating stage promotes the formation of a larger number of monosubstituted groups. Sorption of accompanying metal ions (copper(II), calcium(II), magnesium(II)) is minimal in a wide pH range. The obtained results allow us to purposefully regulate the sorption and selective properties of materials by varying the ratio of functional groups on the surface of the sorbent.