Transformation of LEV-type zeolite into less dense CHA-type zeolite

Goto Ikuhiro

Itakura Masaya

Shibata Syohei

Honda Koutaro

Ide Yusuke

Sadakane Masahiro

Sano Tsuneji

Microporous and Mesoporous Materials

Hydrothermal conversion of LEV-type zeolite into CHA-type zeolite occurred in the absence of both an organic structure-directing agent and a seed crystal. The LEV-CHA transformation proceeds from a more dense zeolite (LEV) to a less dense one (CHA). When amorphous aluminosilicate hydrogels were used as starting materials, the CHA-type zeolite was not obtained under the present hydrothermal synthesis conditions. From the fact that the LEV-CHA transformation proceeded at lower alkalinity conditions, it was suggested that locally ordered aluminosilicate species (nanoparts) produced by decomposition/dissolution of the starting LEV-type zeolite contribute to the transformation process. On the other hand, at higher alkalinity than that used for the CHA-type zeolite synthesis, LEV-LTA transformation occurred effectively and selectively. These results suggest that there is a large difference in the structures of nanoparts generated by decomposition/dissolution of the starting zeolite in the LEV-CHA and LEV-LTA transformations.

Hydrothermal conversion

Interzeolite conversion

LEV-type zeolite

CHA-type zeolite

Less dense zeolite

Biology [ 460 ]

eng

Elsevier Science BV

(c) 2012 Elsevier Inc. All rights reserved.

[ISSN] 1387-1811

[DOI] 10.1016/j.micromeso.2012.03.032

[NCID] AA11538251

[DOI] http://dx.doi.org/10.1016/j.micromeso.2012.03.032