scholarly journals Tracking the crystallization behavior of high-silica FAU during AEI-type zeolite synthesis using acid treated FAU-type zeolite

RSC Advances ◽  
2021 ◽  
Vol 11 (37) ◽  
pp. 23082-23089
Author(s):  
Yuki Sada ◽  
Anand Chokkalingam ◽  
Kenta Iyoki ◽  
Masato Yoshioka ◽  
Tomoya Ishikawa ◽  
...  

A high-silica FAU was obtained during FAU-to-AEI interzeolite conversion using acid treated FAU.

Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 249
Author(s):  
Yasuhisa Hasegawa ◽  
Chie Abe ◽  
Mayumi Natsui ◽  
Ayumi Ikeda

The polycrystalline CHA-type zeolite layer with Si/Al = 18 was formed on the porous α-Al2O3 tube in this study, and the gas permeation properties were determined using single-component H2, CO2, N2, CH4, n-C4H10, and SF6 at 303–473 K. The membrane showed permeation behavior, wherein the permeance reduced with the molecular size, attributed to the effect of molecular sieving. The separation performances were also determined using the equimolar mixtures of N2–SF6, CO2–N2, and CO2–CH4. As a result, the N2/SF6 and CO2/CH4 selectivities were as high as 710 and 240, respectively. However, the CO2/N2 selectivity was only 25. These results propose that the high-silica CHA-type zeolite membrane is suitable for the separation of CO2 from CH4 by the effect of molecular sieving.


2021 ◽  
Vol 319 ◽  
pp. 111044
Author(s):  
Xinluona Su ◽  
Yuta Nakasaka ◽  
Ren Moriwaki ◽  
Takuya Yoshikawa ◽  
Takao Masuda

2018 ◽  
Vol 197 ◽  
pp. 05003 ◽  
Author(s):  
Soni Setiadji ◽  
Citra Deliana Dewi Sundari ◽  
Endang Lala ◽  
Denia Febby Nurbaeti ◽  
Ira Novianti ◽  
...  

T-type zeolite can be used as catalyst, adsorbent, and membranes for gas separation. The synthesis of T-type zeolite needs to be optimized in both of the method and source of precursor, because of its relatively high price. In this research, the synthesis is done using silica extracted from bamboo leaves instead of commercial silica. This increases the value of the bamboo leaves and the cost-performance of zeolite synthesis. The silica was extracted from bamboo leaves ash using alkaline solvent. The extracted silica has 81.76% of purity and an amorphous phase. The T-type zeolite was synthesized using the molar composition of 0.15 Na2O : 0.025 Al : 0.15 K2O : 1 SiO2 : 15 H2O : 0.06 TMAOH, under hydrothermal method and heating process for 4 days, 60°C for 2 days and 120°C for the next 2 days. The characterization method using X-Ray Diffraction and Infra-Red Spectroscopy were performed to confirm the formation of T-type zeolite. The results of Scanning Electron Microscope (SEM) analysis show that the formed T-type zeolite has erionite cylindrical crystal shape.


Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 64 ◽  
Author(s):  
Ying-Wai Cheong ◽  
Ka-Lun Wong ◽  
Boon Seng Ooi ◽  
Tau Chuan Ling ◽  
Fitri Khoerunnisa ◽  
...  

MER-type zeolite is an interesting microporous material that has been widely used in catalysis and separation. By carefully controlling the synthesis parameters, a procedure to synthesize K-MER zeolite crystals with various morphologies has been developed. The silica, water and mineralizer content in the synthesis gel, as well as crystallization time and temperature, have a profound impact on the crystallization kinetics, resulting in zeolite solids with various degrees of crystallinity, crystal sizes and shapes. K-MER zeolite crystals with nanorod, bullet-like, prismatic and wheatsheaf-like morphologies have been successfully obtained. The catalytic performances of the K-MER zeolites in cyanoethylation of methanol, under novel non-microwave instant heating, have been investigated. The zeolite in nanosize form shows the best catalytic performance (94.1% conversion, 100% selectivity) while the bullet-like zeolite gives poorest catalytic performance (44.2% conversion, 100% selectivity).


RSC Advances ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 4900-4907 ◽  
Author(s):  
Daniel Marcos Dal Pozzo ◽  
José Airton Azevedo dos Santos ◽  
Edward Seabra Júnior ◽  
Reginaldo Ferreira Santos ◽  
Armin Feiden ◽  
...  

FFA esterification pre-treatment catalyzed by a Faujasite type zeolite.


2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Enrico Catizzone ◽  
Massimo Migliori ◽  
Alfredo Aloise ◽  
Rossella Lamberti ◽  
Girolamo Giordano

In contrast to high silica zeolites, it is difficult to obtain mesoporosity in zeolites with low Si/Al ratio (e.g., <20) via conventional NaOH-based treatment, making the obtainment of hierarchical zeolites with high acidity a challenging target. In this paper, we report the preparation of hierarchical FER-type zeolite at low Si/Al molar ratio (about 10) by postsynthesis etching involving a sequence of three treatments with NaAlO2, HCl, and NaOH solutions and investigate the effect of both NaAlO2 solution concentration and time of treatment on the textural properties. The obtained materials exhibit a mesoporous volume higher than the parent ferrierite with no significant effect on the sample acidity. The catalytic activity of some samples was investigated in vapour-phase methanol dehydration to dimethyl ether, revealing the superiority of hierarchical zeolites in terms of methanol conversion, although the presence of mesopores causes formation of light hydrocarbons at high temperatures.


2020 ◽  
Vol 12 (2) ◽  
pp. 173-179 ◽  
Author(s):  
Supinya Nijpanich ◽  
Takeshi Hagio ◽  
Yuki Kamimoto ◽  
Ryoichi Ichino

MFI-type zeolite is a crystalline microporous aluminosilicate with an intersecting two-dimensional pore structure and well-defined windows of approximately 0.55 nm. It generally crystallizes in high silica to alumina ratios, leading to a rather hydrophobic character. This makes it an attractive adsorbent for removing organic pollutants from wastewater. However, separating the conventional powdery-zeolites from the media after treatment is difficult because they require considerable time to settle. They also trigger filter clogging. In this work, high silica MFI-type zeolite, namely, silicalite-1, was synthesized on the surfaces of hollow glass microspheres to develop a floating adsorbent with high hydrophobicity. Tetraethylorthosilicate and tetrapropylammonium hydroxide were used as the additional silica source and structure directing agent, respectively. The crystallization of silicalite-1 on hollow glass microspheres was performed using hydrothermal synthesis at 180 °C or 150 °C for 40 h using a precursor sol with a molar composition of 3SiO2:1TPA:14EtOH:286H2O. The surface coverage and crystallinity of the as-prepared samples were optimized, and the floatability and adsorption performance of the optimized sample were investigated. Well-covered microspheres were obtained when hydrothermal synthesis was conducted at 180 °C using 0.5 g of hollow glass microspheres and 15 g of a precursor sol adjusted to pH 12.5. The balance between the dissolution rate of the hollow glass microspheres and the crystallization rate of silicalite-1 appeared to be the key factor in the successful synthesis.


2014 ◽  
Vol 16 (33) ◽  
pp. 17893-17899 ◽  
Author(s):  
A. Ryzhikov ◽  
I. Khay ◽  
H. Nouali ◽  
T. J. Daou ◽  
J. Patarin

A behavior of high pressure intrusion–extrusion of electrolyte solutions in pure silica *BEA-type zeolite depends drastically on electrolyte concentration.


Author(s):  
Khasay R. Samedov ◽  
Ulviya A. Mamedova ◽  
Kerim G. Ragimov ◽  
Zarema A. Jabbarova

High silicate zeolite ZSM-5 on the basis of SiO2–In2O3–NaOH with an organic structure forming agent tetrabutylammonium iodide (TBAI) was synthesized in the temperature range of T = 150–220°C, pH = 9-12, τ = 48-240 h. As initial components, silica gel MSKO containing 86% SiO2, tetrabutylammonium iodide (TBAI), chemically pure NaOH and metallic indium (In) were used which mixed by hydrothermal synthesis. At the end of the synthesis, the solid product was separated from the mother liquor, washed on the filter with distilled water from an excess of alkali and dried at 120 °C, calcined at 550 °C (16 h). The products of hydrothermal crystallization were determined by X-ray (RFA – on the device D2-Phaser "Bruker"), differential thermal (DTA- STA-449 F3 Jupiter NETZSCH), by X-ray diffraction (XRD of brand SRM-18) and infrared spectroscopy (IR on FTIR spectroscopy, Nicolefisio VSA) analysis methods. During the synthesis, it was experimentally established that at T = 200 °C; τ = 240 h; pH≈9-10 molar ratio of components 5.78SiO2∙0.058In2O3∙0.625Na2O∙0.11H2O∙0.95 ((C4H9) 4NJ) – MFI-type zeolite is crystallized. When comparing XRF data with literature data, they were referred to a type zeolite of ZSM-5 differing in high degree of crystallinity. The following chemical composition of the synthesized zeolite (wt.%) was established by the X-ray diffraction (SRM-18) method: SiO2 – 94.01; In2O3 – 4.92; Na2O – 1.06 corresponding to the formula 0.96Na2O:In2O3:88SiO2:10H2O.Forcitation:Samedov Kh.R., Mamedova U.A., Ragimov K.G., Jabbarova Z.A. Synthesis of In-containing high-silica zeolite of ZSM-5 type.Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 8. P. 84-87.


Sign in / Sign up

Export Citation Format

Share Document