Intermediate-stage alkaline earth ion exchange in zeolites X and Y

Abstract

The saturation levels of exchange of alkaline earth ions M²⁺ (Ba²⁺, Ca²⁺, Mg²⁺) in zeolites NaX (SiO₂/A1₂O₃ 2.75) and NaY(SiO₂/Al₂O₃ 4.33) at intermediate stages before equilibrium were found to be dependent on a critical value of the equivalent counterion supply in the solution, given by 2M²⁺/Na⁺. The results suggested that the value of 2M²⁺/Na⁺ at maximum exchange was more dependent on the zeolite structure (e.g. pore geometry) than on its counterion content.