Seed-directed synthesis of zincoaluminosilicate MSE-type zeolites using co-precipitated gels with tetraethylammonium hydroxide as a simple organic structure directing agent

Publication date: February 2018
Source:Microporous and Mesoporous Materials, Volume 257
Author(s): Sibel Sogukkanli, Kenta Iyoki, Shanmugam P. Elangovan, Keiji Itabashi, Natsume Koike, Miku Takano, Yoshihiro Kubota, Tatsuya Okubo
Simplified and efficient synthesis of MSE-type zeolites using tetraethylammonium hydroxide (TEAOH) is extended from aluminosilicate to zincoaluminosilicate by combining with co-precipitated gel technique. The direct crystallization of MSE-type zeolite could be realized from the synthesis gels containing co-precipitated gels which contained homogenously dispersed zinc and aluminum species with a Zn/(Zn + Al) ratio up to 0.4. The overall characterizations revealed that most of the zinc species were incorporated as a heteroatom, and created anionic charges in MSE framework. Based on the ion-exchange characteristics of those samples, it is found that the most of introduced zinc species exhibited two anionic charges per atom, which is expected to be suitable sites for divalent-cation exchange. Since the sample prepared by using Zn/(Zn + Al) ratio of 0.2 (MSE-TEAZn0.2) remained stable after thermal treatment, Ni²⁺ exchange was applied to that sample. The results revealed that MSE-TEAZn0.2 sample exhibited ion-exchange capacity superior to aluminosilicate MSE-TEA sample. Therefore, MSE-TEAZn0.2 sample can be shown as a potential divalent-cation exchanger. In this contribution, it is demonstrated that the simplified synthesis path is a very effective, alternative way to synthesize multipore zeolites containing medium and large pores in the frameworks with different heteroatoms.

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