MFI-type boroaluminosilicate: A comparative study between the direct synthesis and the templating method

✍ Scribed by Wei Zhou; Shi-Yu Zhang; Xiang-Ying Hao; Hao Guo; Cui Zhang; Yin-Qing Zhang; Shuangxi Liu

• Book ID: 104029467
• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 372 KB
• Volume: 179
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2005.12.013

✦ Synopsis

Boroaluminosilicate with MFI zeotype (henceforth B-ZSM-5) was synthesized both via the direct synthesis where ZSM-5 was employed as crystal seed and the templating method by using TPABr as the structure-directing agent (SDA). Characterization based on its structure, bonding, surface acidity, and morphology was performed by powder X-ray diffraction (XRD), 11 B MAS NMR spectrometry, FT-IR spectrometry, pyridine-chemisorption IR spectrometry, and scanning electron microscopy (SEM). The composition of the prepared zeolites was determined by ICP-AES; the zeolite framework stability was investigated by steam treatment. The differences in the physicochemical properties of B-ZSM-5 prepared by the two methods were compared and discussed. In the direct synthesis, increasing initial boron-substitution ratio concomitantly brings about increasing difficulty to prepare pure B-ZSM-5 and, MFI-type borosilicate (free of aluminum) cannot be synthesized; the highest SiO 2 /Al 2 O 3 ratio ¼ 70.64 is received. B-ZSM-5 prepared by the templating method shows remarkable hydrothermal stability than its counterpart prepared by the direct synthesis.