Critical Factors in the Seed‐Assisted Synthesis of Zeolite Beta and “Green Beta” from OSDA‐Free Na⁺–Aluminosilicate Gels

Abstract

Organic structure-directing agent (OSDA)-free synthesis of zeolite beta is a subject of both scientific and industrial interest. Herein, we report a comprehensive investigation into the effects of various parameters on the seed-assisted crystallization of zeolite beta in the absence of OSDA. The crystallization behavior of "OSDA-free beta" is strongly governed by the chemical composition of the starting Na(+)-aluminosilicate gel as well as by the Si/Al ratios of the calcined beta seed crystals, which are prepared using tetraethylammonium hydroxide (TEAOH). Furthermore, OSDA-free beta seed crystals can be used to form zeolite beta, termed "green beta". XRD, scanning electron microscopy, inductively coupled plasma atomic emission spectroscopy, and ²⁷Al magic angle spinning NMR analyses showed that the OSDA-free beta and green beta were of high purity and crystallinity. The nitrogen adsorption-desorption of OSDA-free beta and green beta revealed higher surface areas and larger volumes in the micropore region than those of the beta seeds synthesized with OSDA after calcination. These results provide a robust and reliable process for the environmentally friendly production of high-quality zeolite beta in a completely OSDA-free Na(+)-aluminosilicate system.

Inorganic molecular sieves: Preparation, modification and industrial application in catalytic processes

“…Again, it is concluded that the commercial viability of a new structure will be determined mainly by its unique performance and production costs. We would like to highlight here a very interesting new avenue that involves the synthesis of zeolites that were previously done with organic structure directing agents, and can now be synthesized in an organic free synthesis media, though large amounts of seeds have to be used [36][37][38][39][40].…”

“…Some zeolites synthesized in the absence of OSDA are ZSM-34 [36,38], ZSM-12 [39], ECR-1 or beta [37,40]. A second generation of organotemplate-free beta has been presented recently (IZC-IMMS 2010) as "Green Beta".…”

Rational synthesis of Beta zeolite with improved quality by decreasing crystallization temperature in organotemplate-free route

“…Later, Majano et al also reported seeded synthesis of Beta zeolite by the use of a little Beta nanocrystals containing small amount of organic template in the absence of additional organic templates [37]. Subsequently, Kamimura et al demonstrated the effects of initial gel composition, quantity of seed crystals, and crystallinity of the seeds, as well as the Si/Al ratios on the crystallization behavior of the Beta phase [38,39]. Xie et al have demonstrated the core-shell structure mechanism on the formation of Beta zeolite from seeds-directed synthesis (Beta-SDS) [40].…”

Hydrothermal Transformation of Natural Zeolite from Ende-NTT and Its Application as Adsorbent of Cationic Dye

“…In addition, the CEC increased from 84.154, 81.042, and 77.474 cmol/kg, respectively, to 244.063, 216.354, and 211.432 cmol/kg, respectively 37,394, 37,365, dan 37,360 mg/g. Selain itu,15, 81,04, dan 77,47 cmol/kg meningkat menjadi 244,06, 216,35, dan 211,43 cmol/kg. Model Langmuir lebih sesuai untuk proses kesetimbangan adsorpsi isotermal.…”