MCM-22 Zeolite-Induced Synthesis of Thin Sodalite Zeolite Membranes

Abstract

A novel strategy for synthesizing the high-performance thin and compact sodalite zeolite membrane over rough α-Al2O3 support was developed. The synthesis involved the deposition of a layer of flaky MCM-22 zeolite crystals over support and the subsequent hydrothermal crystallization of sodalite zeolite. It was identified that the sodalite zeolite membrane possessed a thickness of ca. 700 nm with almost no defect, and a water/ethanol separation factor higher than 10 000 at a permeation flux of 4.4 kg·m–2·h–1 could be achieved. A possible mechanism for the formation of high-performance sodalite zeolite membrane was also proposed, which involved first the decomposition of MCM-22 zeolite crystals into small fragments containing double six-membered rings (D6R) and subsequently the nucleation and crystallization of sodalite initiated by the D6R-containing species over the surface of support from the strongly alkali synthesis sol. The study showed that the predeposition of a layer of flaky MCM-22 zeolite crystals over the surface of support was crucial for the generation of thin and compact sodalite membranes, as it not only improved the surface flatness but also led to the in situ nucleation and crystallization of sodalite zeolite crystals. This method combines 2D-material film-forming technology with 3D-material film-forming technology, thus providing a new approach for preparing thin and defect-free membranes.

MoO3 Nanobelt-Modified HMCM-49 Zeolite with Enhanced Dispersion of Mo Species and Catalytic Performance for Methane Dehydro-Aromatization

“…The absorption peaks at 675.02 and 549.71 cm −1 are caused by the double six-ring (D6R) vibration in the HMCM-49 zeolite, and are typical characteristic absorption peaks of microporous zeolite [ 34 ]. The peak at 443.62 cm −1 is caused by T−O bending vibration in TO 4 (T is Si or Al), and the above-infrared absorption peak indicates that the synthesized material is HMCM-49 zeolite [ 35 ]. Furthermore, it is revealed that when Mo species are loaded onto HMCM-49 zeolite, the position of the sample characteristic absorption peak does not change, and the absorption intensity decreases, indicating that the Mo species have been dispersed into the zeolite channel, which may also damage the material structure to a certain extent.…”

“…The absorption peaks at 675.02 and 549. caused by the double six-ring (D6R) vibration in the HMCM-49 zeolite, and characteristic absorption peaks of microporous zeolite [34]. The peak at 443 caused by T−O bending vibration in TO4 (T is Si or Al), and the above-infrared peak indicates that the synthesized material is HMCM-49 zeolite [35]. Further revealed that when Mo species are loaded onto HMCM-49 zeolite, the position ple characteristic absorption peak does not change, and the absorption intensity indicating that the Mo species have been dispersed into the zeolite channel, w also damage the material structure to a certain extent.…”

Study of the Relationship between Synthesis Descriptors and the Type of Zeolite Phase Formed in ZSM‐43 Synthesis by Using Machine Learning

“…In their study, Wei et al converted MCM-22 lamellar structure into sodalite zeolite by treating it with high levels of hydroxide ions. [28] The framework zeolite of MCM-22 is destroyed, but the basic ring structures (S6R and/or D6R) are preserved and facilitate the formation of sodalite zeolite. During the conversion of MCM-22 to sodalite, intermediate phases such as LTA FAU are formed.…”

In situ constructed zeolite membranes on rough supports with the assistance of reticulated hydrotalcite interlayer

“…The zeolite membrane synthesis solution was prepared via a similar procedure reported elsewhere. 24 Briefly, sodium silicate solution was first prepared by dissolving sodium hydroxide in a colloidal silica solution under heating and stirring, then, it was cooled to room temperature and mixed with sodium aluminate aqueous solution under agitation. The synthesis solution was vigorously stirred for 24 h before using it for the synthesis of NaA zeolite membrane.…”