Synthetic zeolite NaA was prepared from Hadong kaolin in sodium hydroxide solution. The properties and structures of the exchanged zeolite NaA with thallium, rubidium, cesium, strontium, mercury, lanthanum, cerium, iron, chromium, and aluminium ion were studied.
From the ion exchange isotherm and standard Gibb's free energy of ion exchange, the ion exchange selectivity was in the order Ti⁺>Rb⁺>Cs⁺ for univalent ion and Sr²⁺>Hg²⁺ for divalent ion.
The pH range of trivalent solution used in this experiment was 3 to 6, and the structure of ion exchanged zeolite was seriously destroyed in comparison with zeolite NaA in the same pH of the distilled water solution.
By comparison of the exchanged crystalline structure with La³⁺, Ce³⁺ on each temperature, it was shown that crystalline structure was seriously destroyed at high temperature.