Superior Ion‐exchange Property of Amorphous Aluminosilicates Prepared by a Co‐precipitation Method

Abstract

The development of inexpensive inorganic ion‐exchangers for the purification of environmental pollutants is a social demand. Amorphous aluminosilicates with a relatively high homogeneous Al environment are prepared by a feasible co‐precipitation method, i. e., mixing an acidic aluminum sulfate solution and basic sodium silicate solution, which exhibit excellent ion‐exchange selectivity for Cs+ and Sr2+. The Kd value for Sr2+ was comparable with that of zeolite 4A. The local structures and ion‐exchange behavior of the amorphous aluminosilicates are systematically investigated. The ion‐exchange property of the amorphous aluminosilicates can be tuned by changing the interaction between the exchangeable cation and the amorphous aluminosilicates. Also, the amorphous aluminosilicates can adsorb bulky cations that zeolites hardly adsorb due to the limitation of the miropore size of zeolites.