Beneficial Use of Ultrasound in Rapid-Synthesis of SAPO34/ZSM-5 Nanocomposite and Its Catalytic Performances on MTO Reaction

Abstract

SAPO-34 is highly selective and hydrothermally stable for MTO reactions but it is rapidly deactivated by the formation of coke through its micropores. The promising SAPO-34/ZSM-5 nanocomposite catalyst with a different ratio was synthesized by the ultrasonic-assisted hydrothermal method and it obtained products that were characterized to further investigate their catalytic performance. Utilization of the ultrasound method led to a faster synthesis time, a decrease of crystallite size, an increase of surface area, and a dominant mesopore structure. The physicochemical properties of the product were extensively investigated by XRD, FESEM, TEM, FT-IR, N2 adsorption–desorption techniques, and NH3-TPD. Results indicate that the composite had high conversion and selectivity compared to that of the original ZSM-5 and SAPO-34. When composite structures due to the synergic effect between ZSM-5 and SAPO-34 acted as promoted catalysts, they improved catalytic properties of composite catalysts. Moreover, the SAPO-34/ZSM-5 nanocomposite catalyst with 50% ratio synthesized by the ultrasonic-assisted hydrothermal method (U–S/Z (50%)) showed 100% conversion and 90% selectivity to light olefin at 450 °C.

Quenching the Deactivation in the Methanol-to-Olefin Reaction by Using Tandem Fixed-Beds of ZSM-5 and SAPO-18 Catalysts

“…The SAPO-34/ZSM-5 composite catalyst, synthesized by a two-step in situ crystallization method, showed an improved catalytic life with a methanol conversion of 97% and a selectivity of light olefins of 93% . Other authors − have also reported synergetic effects of SAPO-34/ZSM-5 by adjusting both acid and physical properties (hierarchical mesoporous structure). The benefits are related to higher olefin formation, better dispersion of both phases, increased catalyst site accessibility, because of direct connection of hierarchical matrix structure, and improved catalytic lifetime.…”

Synthesis and Applications of SAPO‐34 Molecular Sieves

“…According to the literature, it is found that the application of ultrasound leads to improving influences on nucleation process, crystal growth rate, crystallite size, morphology, and particle size distribution [107–109] . Moradiyan et al [110] . found that utilization of the ultrasound method led to a faster synthesis time, a decrease of crystallite size, an increase of surface area, and a dominant mesopore structure.…”

Ultrasound-assisted rapid hydrothermal design of efficient nanostructured MFI-Type aluminosilicate catalyst for methanol to propylene reaction

“…Zhuang et al [32] synthesized well-ordered ZSM-5 crystals with tunable mesoporosity and high catalytic stability for propylene production from methanol by using a facile ultrasound-assisted approach. Moradiyan et al [33] reported that utilizing of ultrasound-assisted conventional hydrothermal method for preparation of SAPO-34/ZSM-5 nano composite resulted in a rapid synthesis and formation of dominant mesopore structure with unique properties. Hence, the use of ultrasound along with high temperature hydrothermal synthesis as alternative routes is proposed for preparation of MFI aluminosilicate framework.…”