Acid-Base Properties of Macroporous Weak Base Anionite Based on Aminated Acrylonitrile/Divinylbenzene Copolymer

摘要

Potentiometric titration of weak base anionite (the degree of crosslinking was 12-16%) was performed within the pH range of 2-12 and NaCl concentration range of 0.1-1.0 mol/L. The maximum ion-exchange ability against HCl does not depend on the solution ionic strength and is 6.50 perpendicular to 0.12 mmol/g of dry solid matter. It was shown that the process of acid-base equilibrium can be adequately described by the Gregor equation within the studied stock electrolyte concentration and pH ranges. Two type of groups were discovered in anionite. The ionization constants of these groups differ by three orders of magnitude. The existence of amino groups of different nature was proved by the data obtained by functional analysis; it was estimated that the acidity of these groups decreases as NaCl concentration increases.