The Kinetics of Sorption Extraction of Lanthanum and Aluminum Cations from a Phosphoric Acid Solution by Sulfocathionite

The kinetics of sorption extraction of Al and La cations from a solution of phosphoric acid by synthetic macroporous cation exchange resin was studied. In order to obtain the limiting stage of the process, the kinetic data obtained at various temperatures were approximated by pseudo-first, pseudo-second-order models, as well as the Boyd model for various cases of diffusive drag. It was found that the kinetics of adsorption of lanthanum ions is determined primarily by the rate of surface chemical reaction, while the adsorption of aluminum ions is limited by diffusion processes. A probable reason for the selectivity of adsorption may be the formation of complex compounds of different shapes and strengths between metal cations and phosphate anions.