Role of crystal growth modifiers in the synthesis of ZSM-12 zeolite

摘要

The effects of crystallization time, temperature and aging time on the synthesis of pure ZSM-12 in the presence of polyethylene glycol (PEG) and polyoxyethylene Brij-35 surfactant with fixed ratios of Si/Al (160) and Na/SiO2 (0.144) were systematically investigated. Larger synthesis window and high purity of ZSM-12 were expected. Pure phase of ZSM-12 was obtained when PEG was added to the synthesis mixture with PEG/Al2O3 ratio in the range of 0.4-2. Furthermore, the addition of both Brij-35 and PEG in the synthesis was found to play a significant role in controlling the crystallization rate. The Brij-35/Al2O3 ratio was varied from 0 to 4.9. Conventional ZSM-12 was typically synthesized at 145 degrees C for 120 h. Shorter crystallization time of 60 h was achieved when PEG/Al2O3 ratio of 1.22 and a Brij-35/Al2O3 ratio of 1.61 was used in the synthesis. (C) 2014 The Society of Powder Technology Japan. Published by Elsevier B. V. and The Society of Powder Technology Japan. All rights reserved.