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.