Synthesis of Zeolite from Glass
Masato TSUJIGUCHI, Tadashi KOBASHI, Junji KANBARA, Yasuhiko UTSUMI, Nobuaki KAKIMORI and Atsushi NAKAHIRA
Abstract:Zeolite is a microporous aluminosilicate material with uniform pore size of less than 2 nm and chemical, mechanical, and thermal stability. In general zeolite is synthesized from silica, alumina, mineralizer (alkali metal hydroxide and fluoride) and water. On the other hand, the production volume of various kinds of high-quality glass which are utilized for high-tech products such as liquid crystal displays and plasma displays is rapidly increasing. We tried to synthesize zeolite from an aluminoborosilicate glass which is used in LCD panel glass substrate and mainly composed of silica and alumina. By using only aluminoborosilicate glass powders, zeolite was synthesized at synthesis temperature higher than 423K and the synthesized samples had GIS type zeolite or ANA type zeolite related structure according to XRD analysis. We investigated the effect of Si/Al ratio and NaOH concentration to zeolite synthesis. In the range of Si/Al was 5.0 to 7.5, GIS type zeolite which has tetragonal structure was synthesized with 0.2M NaOH and 1.0M NaOH, though, by using only aluminoborosilicate glass powder, cubic GIS type zeolite has synthesized. It is because crystal structure of GIS type zeolite depends on chemical composition. In the case of Si/Al=10.0, ANA type zeolite was synthesized with dilute NaOH solution and GIS type zeolite was synthesized with concentrated NaOH solution. From SEM observation, the products had the surface structures specific to zeolite. It was thought that zeolite was successfully synthesized from the aluminoborosilicate glass by hydrothermal processing. And kind of zeolite synthesized depended on Si/Al ratio and concentration of NaOH solution. Key Words:Zeolite, Glass, Hydrothermal processing, XRD, SEM