Chemical properties of N-2-Sulfoethylchitosan with a medium degree of substitution

A method was developed for the preparation of N-2-sulfoethylchitosan (SECH) via synthesis in a gel with the use of the reaction of chitosan and sodium 2-bromoethanesulfonate. This method makes it possible to conduct a polymer-like transformation without any acid or base. The structures of the obtained polymers were confirmed via IR and ¹H NMR spectroscopy. The study of the sorption of Ag⁺, Cu²⁺, Zn²⁺, Ni²⁺, Co²⁺, Cd²⁺, Pb²⁺, Mn²⁺, Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺ ions that were crosslinked by SECH during their joint presence in an ammonia-acetate buffer solution showed high values of selectivity in relation to those of silver(I) and copper(II). The selectivity of the sorption of silver(I) ions with respect to copper(II) ions increased with an increase in the degree of substitution of SECH.