KINETICS OF POLYMER CARRIER IMPREGNATION BY TRIALKYLAMINE

Abstract

The immediacy of the problem under study is due to the lack of data on the kinetics of polymer carrier impregnation with extraction agents. The article is aimed at obtaining the kinetic characteristics of the impregnation of a polymeric macroporous carrier—a weakly acidic cation resin with carboxyl groups—with trialkylamine and its solutions in acetone. The integral kinetic curves of the extraction agent adsorption on the carrier were obtained. This allowed estimating the time of equilibrium by the limited solution volume method. This time was 25-30 hours, decreasing with the application of a dilution agent and with the increase in temperature. The kinetic impregnation characteristics were calculated by means of the pseudo-second-order, Elovich, and internal diffusion models. The pseudo-second-order model describes the experimental kinetic data with a high correlation degree (R2 0.995-0.997) and points out that interaction with two sorption centres possibly takes place with the adsorption of a single trialkylamine molecule. The impregnation rate constants via an extraction agent were calculated using all kinetic models. Based on the apparent activation energy magnitude (37±14 kJ/mol), it can be assumed that diffusion is the rate-limiting step of the impregnation process. This article can be useful for creating impregnates containing extraction agents of various classes.