Pathways in particle assembly by ultrasound-assisted spray-drying of kaolin/SAPO-34 as a fluidized bed catalyst for methanol to light olefins

Aghamohammadi, Sogand; Haghighi, Mohammad; Ebrahimi, Alireza

doi:10.1016/j.ultsonch.2019.01.009

Cited by 16 publications

(1 citation statement)

References 55 publications

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“…В то время как динамическая активность по парам воды цеолита LTA_ГТК ниже на 10% и находится в пределах от 16,9 до 18,2 г/100 г сорбента. Данный факт объясняется тем, что обработка ультразвуком способствует формированию структуры цеолита типа LTA [15][16][17], обладающей большей адсорбционной емкостью, чем промышленный аналог. Кроме того, цеолиты исследовались на механическую прочность в зависимости от количества циклов регенерации (табл.…”

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Comparative Analysisof the Properties of Lta Type Zeolite Depending on the Production Method: Hydrothermal and Ultrasonic

2022

Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.

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The aim of the work was to establish the main parameters of the study of the use of ultra-sound at the stage of synthesis in search of the physicochemical properties of the LTA type zeolite with the hydrothermal method of production. A maincondition for the synthesis of this zeolite is the presence of precursors, namely aluminates and cubic sodium aluminosilicates. Metakaolin, solid sodium hydroxide and aluminum oxide are used as raw materials for the synthesis of zeolite. Ultrasonic treatment is carried out at a frequency of 22 kHz and a frequency of 8 μm at the end ofthe concentrator for 10 min. The industrial analogue was synthesized according to TU 2163-005-21742510-2004. In this work, ammonia is used as a probe to study the acid–base properties of zeo-lite structures. The choice of ammonia is due to the high degreeof bases, which makes it possible to determine not only strongly acidic centers, but also to combine centers that determine the size of molecules. Dynamic activity in terms of water parameters at breakthrough concentration is ob-served in the flow protocol. The particle size of zeolites is measured by scanning electron micros-copy. It was found that in the sample synthesized using ultrasound, the concentration of exchangeable sodium cations is 2.5 times higher than in the hydrothermal analogue and is 80 and 30 μg-eq/100g, respectively. The strength and number of acid sites of the synthesized zeolites were determined by the method of thermally programmed desorption of ammonia. For the synthesized LTA zeolite, its values are in the range of 0.06 1019 U/m2, for the industrial analogue it is lower by 5-10% and rarely 0.05 1019 U/m2. Using the data on the kinetics of ammonia desorption at various heating rates, the values of activation energy for ammonia desorption were calculated. The results lie in the range from 18.26 to 74.27 kJ/mol. The study of acid-base properties showed a more developed sur-face of the zeolite obtained by the ultrasonic method, which explains the greater acidity and acti-vation energy.

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Comparative Analysisof the Properties of Lta Type Zeolite Depending on the Production Method: Hydrothermal and Ultrasonic

2022

Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.

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Influence of surface design on performance of MnO‐decorated nanocatalyst for olefin production from methanol: ZSM‐5@MnO core–shellversusMnO/ZSM‐5 dispersed nanocatalysts

Khaledi

Haghighi

Sadeghpour

2020

J of Chemical Tech & Biotech

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BACKGROUNDIn the assembly of nanoparticles (NPs) onto zeolites, the surface design of NPs has a great influence on various catalytic properties. Herein, ZSM‐5 was hydrothermally synthesized and its external surface was decorated by MnO NPs in two different surface designs: distributed MnO NPs and MnO shell.RESULTSThe synthesized MnO‐decorated samples, MnO/ZSM‐5 and ZSM‐5@MnO, were analyzed using various techniques. The results of these analyses reveal the formation of desired crystal phases without any impurities and confirm the perfect assembly of uniform MnO NPs on the surface of ZSM‐5. Also, it was found that the surface design of MnO NPs has a great impact on the physicochemical properties of the nanocatalyst. Basically, ZSM‐5 is highly selective toward propylene, but the shape selectivity of MnO NPs increases the selectivity of MnO‐decorated nanocatalysts toward ethylene. Moreover, this study delves deeply into differences in catalytic behaviors of the nanocatalysts during the methanol‐to‐olefin process and explains how they are attributed to the applied surface designs.CONCLUSIONSThe catalytic performance studies at optimum temperature show that the ZSM‐5@MnO nanocatalyst is more selective toward ethylene, and it has a nearly 20% higher methanol conversion rate compared to the MnO/ZSM‐5 nanostructured catalyst. Due to the surface acidity adjustment of MnO shell as well as high control of core–shell structure over the location of coke formation, the ZSM‐5@MnO nanocatalyst shows longer stability and its activity remains constant with time on stream. © 2020 Society of Chemical Industry

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Morphology/crystallographic evolution of nanostructured SAPO-34 using simultaneous surfactant and Si source towards production of lower olefins: enhancement of lifetime and regenerative properties

et al. 2022

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Pathways in particle assembly by ultrasound-assisted spray-drying of kaolin/SAPO-34 as a fluidized bed catalyst for methanol to light olefins

Cited by 16 publications

References 55 publications

Comparative Analysisof the Properties of Lta Type Zeolite Depending on the Production Method: Hydrothermal and Ultrasonic

Comparative Analysisof the Properties of Lta Type Zeolite Depending on the Production Method: Hydrothermal and Ultrasonic

Influence of surface design on performance of MnO‐decorated nanocatalyst for olefin production from methanol: ZSM‐5@MnO core–shellversusMnO/ZSM‐5 dispersed nanocatalysts

Morphology/crystallographic evolution of nanostructured SAPO-34 using simultaneous surfactant and Si source towards production of lower olefins: enhancement of lifetime and regenerative properties

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