2000 Volume 108 Issue 1262 Pages 898-903
The uptake of various cations by imperfectly ordered KAlSiO4 was investigated. The KAlSiO4 was prepared by solid-state reaction of kaolinite with K2CO3 at 550°C for 24h. Uptake experiments were performed at 60°C using 0.5g of the KAlSiO4 and 50ml of solution containing 10-3-10-1M of each cation, with and without 0.5M NaCl buffer. The cations were alkali (Li+ and Na+), alkaline earth (Mg2+, Ca2+, Sr2+ and Ba2+) and transition metal cations (Ni2+, Co2+, Cu2+ and Zn2+). From the comparison of uptakes of various cations by KAlSiO4 and zeolite Na-A, it was found that the ratio of uptake by both exchange materials increased with decreasing ionic radius of the exchanging cations, the KAlSiO4 showing higher uptake of Ni2+ than zeolite Na-A. This trend became more distinct for the uptake of Ni2+ in simulated acid waste solution and groundwater because of the suppressing effects by co-existing alkali and alkaline earth cations especially for zeolite Na-A.