Solvothermal Synthesis of −LIT-type Zeolite

Lithosite (−LIT) type aluminosilicate zeolites were successfully synthesized, for the first time, by solvothermal treatment of low-silica zeolite powders. The starting materials comprised H–Y zeolite samples having different SiO2/Al2O3 ratios, together with NH3+-exchanged chabazite and NH3+-exchanged phillipsite. The low-silica zeolite powders were dispersed in alcohol containing dissolved KOH, and the mixture was solvothermally treated at 200–250 °C for 15–120 h without stirring. The crystal structure of the obtained sample was analyzed by the Rietveld method which indicated it to be single phase –LIT zeolite (monoclinic, space group P21, a = 1.513 nm, b = 1.023 nm, c = 0.842 nm, β = 89.99°). The scanning electron microscopy images show that the obtained product consists of blade-like particles. The SiO2/Al2O3 ratios of the –LIT samples varied from 4.0 to 6.7 based on the composition of the starting materials. The zeolite pores were hydrophilic in nature; however, potassium cations contained in the micropores were hardly exchanged at room temperature. Furthermore, Co-substituted –LIT zeolite was also successfully synthesized by a similar method as that used for –LIT-type aluminosilicate zeolite, using Co2+-exchanged H–Y zeolite as the starting material.