scholarly journals Separation of Ethanol-Water MixtureUsing Type-A Zeolite Molecular Sieve

2010 ◽  
Vol 7 (2) ◽  
pp. 483-495 ◽  
Author(s):  
Juan Camilo Díaz ◽  
Iván Darío Gil-Chávez ◽  
Liliana Giraldo ◽  
Juan Carlos Moreno-Piraján
Keyword(s):  
Molecular Sieves ◽  
Molecular Sieve ◽  
Type A ◽  
Water Mixture ◽  
X Ray Diffraction ◽  
Experimental Procedure ◽  
X Ray ◽  
Promoter Characterization ◽  
Reactive Mixture

This paper presents an experimental procedure for the synthesis of a type-A zeolite molecular sieve, usable in the separation of an ethanol-water mixture. The type-A zeolite molecular sieve is obtained from a reactive mixture formed by a source of alumina, a source of silica and a promoter. Characterization of the molecular sieves obtained in this work was undertaken using X-ray diffraction (XRD), adsorption isotherms and scanning electron microscopy (SEM). The results from the characterization procedures showed that part of the product presented a pore diameter suitable for the separation of an ethanol-water mixture.

Influence of Substituting Al by Mg-Co and Mn-Co on the Properties of AlPO4-5

1992 ◽  
Vol 57 (4) ◽  
pp. 750-755 ◽  
Author(s):  
Liao Changsheng
Keyword(s):  
Catalytic Activity ◽  
Infrared Spectra ◽  
Molecular Sieves ◽  
Molecular Sieve ◽  
Surface Acidity ◽  
Chemical Compositions ◽  
Hydrothermal Crystallization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystallization Method

Two kinds of crystalline microporous metal aluminophosphate molecular sieves, magnesium cobalt aluminophosphate (MgCoAPO-5) and manganese cobalt aluminophosphate (MnCoAPO-5), were synthesized by hydrothermal crystallization method in order to improve the surface acidity and catalytic activity of AlPO4-5. The results of X-ray diffraction, infrared spectra and chemical compositions of MgCoAPO-5 and MnCoAPO-5 indicate that Mg-Co or Mn-Co enter the framework of AlPO4-5 molecular sieve without disrupting the microporous framework. However, the results of catalytic studies show that MgCoAPO-5 and MnCoAPO-5 possess much higher surface acidity and catalytic activity than the unmodified AlPO4-5.

scholarly journals Synthesis and Characterization of a New Aluminosilicate Molecular Sieve from Aluminosilica Perhydrate Hydrogel

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5469
Author(s):  
Haiqiang Ma ◽  
Kun Jiao ◽  
Xiangyu Xu ◽  
Jiaqing Song
Keyword(s):  
Molecular Sieves ◽  
Molecular Sieve ◽  
Critical Factor ◽  
Synthesis And Characterization ◽  
X Ray ◽  
Cell Parameters ◽  
Structure And Morphology ◽  
Novel Structure ◽  
Pure Phase

A novel structure aluminosilicate molecular sieve, named BUCT-3, was prepared by dynamic hydrothermal synthesis, and the critical factor to obtain the new structure is using an active silicon and aluminum source, aluminosilica perhydrate hydrogel. Meanwhile, only high content of O-O bonds can ensure the pure phase of BUCT-3. Through the characterization of x-ray powder diffraction (XRD), Fourier transform infrared spectra (FTIR), scanning electron microscopy (SEM), and so on, some structure and morphology information of BUCT-3 molecular sieves as well as the special silicon and aluminum source was obtained. It’s worth noticing that the O-O bonds of reactants can be reserved in the products, and thus, help us to get a new structure with cell parameters a = 8.9645 Å, b = 15.2727 Å, c = 11.3907 Å, α = 90°, β = 93.858°, γ = 90°. The crystal system is monoclinic. Though the thermostability of BUCT-3 is not satisfactory, its potential application derived from O-O bonds cannot be neglected.

Investigating the properties and performance of 3A molecular sieves as an adsorbent to prevent coke formation in olefin dehydration process

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Zoya Moslempour ◽  
Sepehr Sadighi ◽  
Ali Dashti ◽  
Ali Ahmadpour
Keyword(s):  
Molecular Sieves ◽  
Molecular Sieve ◽  
Coke Formation ◽  
Chemical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Na Ions ◽  
Temperature Programmed ◽  
And Performance ◽  
Physical And Chemical

Abstract To study the affinity of 3A aluminosilicate adsorbents to prevent oligomerization of olefin molecules and forming green oil, physical and chemical properties of 3A molecular sieves are measured by using characterization techniques such as temperature-programmed desorption (TPD), nitrogen (N2) and water adsorptions, X-ray diffraction (XRD), X-ray fluorescence (XRF), crushing strength, and carbon dioxide (CO2) adsorption. Moreover, coke formation affinities of the understudy adsorbents are evaluated in a bench-scale system using 1-butene and 1,3-butadiene at temperatures of 220 and 260 °C, and outcomes are validated against the actual data gathered from an industrial scale olefin dehydration plant. Results confirm that the type of binder and the amount of ion exchange affect the performance of a 3A molecular sieve nominated for dehydrating olefinic streams. The binder with the least amount of acidity is preferred, and at least 35% of Na ions of the 4A zeolite should be exchanged with K ions to make it applicable for synthesizing an appropriate 3A molecular sieve. Furthermore, to control the oligomerization and inhibit green oil formation, the CO2 adsorption and acidity of Trisiv shape molecular sieves with the sizes of 1/4 inch should be less than 0.5 wt % and 1.7 mmol NH3/g, respectively. For extrudate shape with the sizes of 1/16 inch CO2 adsorption and acidity should be less than 0.2 wt % and 2.2 mmol NH3/g, respectively.

Synthesis and Characterization of Co/SBA-15 Catalysts

2016 ◽  
Vol 881 ◽  
pp. 35-40
Author(s):  
Franciele Oliveira Costa ◽  
Carla Gabriela Azevedo Misael ◽  
André Miranda da Silva ◽  
Bianca Viana de Sousa
Keyword(s):  
Molecular Sieve ◽  
Pore Diameter ◽  
Mesoporous Structure ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Wet Impregnation ◽  
X Ray ◽  
Different Temperatures ◽  
Temperature Programmed

The mesoporous silica SBA-15 molecular sieve has been widely studied due to its unidirectional mesoporous structure, its high average pore diameter, its high thermal and hydrothermal stability and its ability to absorb metal ions, allowing its use as support material for catalysts. This study aimed to synthesize the Co/SBA-15 catalyst, and characterize it through the techniques of X-ray diffraction, temperature programmed reduction (TPR) and scanning electron microscopy (SEM). The SBA-15 support was synthesized from the following molar composition of reaction mixture: 1TEOS: 0.017 P123: 5.7 HCl: 173 H2O: 40 EtOH, and after calcined at 550 °C for 6 hours. The Co/SBA-15 catalyst was prepared by incorporating 10% cobalt by wet impregnation. Through the X-ray diffractograms, it was found that the impregnation has not changed the structure of the material. RTP profiles showed the presence of peaks at different temperatures that may be caused by dispersion of the cobalt.

Synthesis and Characterization of the Catalysts 5 wt.% and 10 wt.% Co/SBA-15

2010 ◽  
Vol 660-661 ◽  
pp. 561-566
Author(s):  
L.A. Lima ◽  
B.V. Sousa ◽  
Meiry Glaúcia Freire Rodrigues
Keyword(s):  
Ethylene Oxide ◽  
Molecular Sieve ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Poly Ethylene Oxide ◽  
Desorption Isotherms ◽  
Poly Ethylene ◽  
Adsorption Desorption

Catalysts supported on SBA-15 were obtained by wet impregnation using aqueous solution of cobalt nitrate, where different contents of cobalt (5 wt% and 10 wt%) were prepared. The molecular sieve SBA-15 was synthesized using tetra ethyl ortho silicate (TEOS) as silicate source, and triblock copolymer, poly-(ethylene oxide)-poly (propylene oxide)-poly-(ethylene oxide) PEO-PPO-PEO as the organic structure directing agent. These materials were characterized by X-ray diffraction (XRD), X-ray energy dispersion spectrophotometer (EDX) and Nitrogen adsorption–desorption isotherms (BET). The results from the XRD showed that the molecular sieve mesoporous (SBA-15) was identified by X-ray diffraction, especially from the (210) and (300) peaks, which represent a typical spectrum for the SBA-15. Characterization of catalysts by Nitrogen adsorption–desorption isotherms (BET) made it possible to verify the the samples had been of type IV with hysteresis of corresponding the H2 type the porous materials.

Preparation and Characterization of Hierarchical Pore Molecular Sieve with Large Pore Size

2016 ◽  
Vol 859 ◽  
pp. 62-67
Author(s):  
Min Li ◽  
Dong Liu ◽  
Yue Lun Wang ◽  
Ya Dong Zhang ◽  
Ran Yu ◽  
...  
Keyword(s):  
Pore Size ◽  
Molecular Sieves ◽  
Fixed Bed ◽  
Cobalt Nitrate ◽  
Fixed Bed Reactor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hierarchical Pore ◽  
Adsorption Desorption

A series of hierarchical pore molecular sieves (HPMSs) with pore size up to 6.0 nm were prepared using triblock copolymer (P123) as mesoporous template agent and characterized by N2 adsorption-desorption. Cobalt-loaded catalysts were prepared by impregnating cobalt nitrate onto HPMSs and characterized by X-ray diffraction and scanning electron microscopy. The result indicates that mesopore size of HPMS increased along with the increment of the amount of P123. The selectivity of the catalysts for Fischer-Tropsch synthesis was evaluated in a fixed-bed reactor, and the results show that the selectivity of C12+ hydrocarbons is increased with the increment of the pore size.

Synthesis and Characterization of Molecular Sieve SBA-15 and Catalysts Co/SBA-15 and Ru/Co/SBA-15

2014 ◽  
Vol 798-799 ◽  
pp. 100-105 ◽  
Author(s):  
Jocielys Jovelino Rodrigues ◽  
Liliane Andrade Lima ◽  
Gustavo Medeiros de Paula ◽  
Meiry Glaúcia Freire Rodrigues
Keyword(s):  
Molecular Sieve ◽  
High Surface ◽  
Nitrogen Adsorption ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Bet Method ◽  
Superficial Area

A series of mesoporous materials have been synthesized in an acid medium, with various structures, such as SBA-15. These materials have many properties which make them potential catalysts. Among these we highlight their high surface areas and pore walls relatively thick, resulting in a greater hydrothermal stability. This work aims at the synthesis and characterization of molecular sieve SBA-15 with molar composition: 1.0 TEOS: 0.017 P123: 5.7 HCl: 193 H2O and Co/SBA-15 and catalysts for the reaction of Ru/Co/SBA-15 Fischer Tropsch process. The materials were characterized by the techniques of X-ray diffraction (XRD), chemical analysis by X-ray spectrometry, energy dispersive (EDX) and Nitrogen adsorption (BET method). X-ray diffraction showed that the calcined cobalt catalyst did not modify the structure of SBA-15 and that Co was present under the form of Co3O4 in the catalyst. The addition of cobalt in the SBA-15 decreased the specific superficial area of the molecular sieve.

Low Temperature Studies Of Rare Gases Adsorbed On Molecular Sieve Materials

1991 ◽  
Vol 233 ◽  
Author(s):  
Graham F. Mccann ◽  
I. Gameson ◽  
W.J. Steado ◽  
T. Rayment ◽  
P.J. Barrie ◽  
...  
Keyword(s):  
Low Temperature ◽  
Phase Transformations ◽  
Adsorption Isotherms ◽  
Low Temperatures ◽  
Molecular Sieves ◽  
Molecular Sieve ◽  
Variable Temperature ◽  
Rare Gases ◽  
X Ray Diffraction ◽  
X Ray

ABSTRACTX-ray diffraction (XRD) and adsorption isotherms have long been traditional methods of characterising molecular sieves. By combining these techniques at low temperatures with variable temperature 129-Xe N.M.R. we now have a fuller understanding of the behaviour of sorbed layers inside these materials. In particular we have observed phase transformations of Xe in a polyhydroxyaluminium-pillared montmorillonite molecular sieve and have developed a model consistent with the data. In addition, using XRD, an interpillar distance of ca. 30Å was calculated. We present the first detailed low temperature studies of 129-Xe N.M.R. on these systems.

Preparation of Molecular Sieve Al-SBA-15 with Two Ratios Si/Al Catalyst for Use in the Transesterification Reaction of Soybean Oil

2018 ◽  
Vol 912 ◽  
pp. 39-43
Author(s):  
Janaína C. Marinho ◽  
Tellys. L.A. Barbosa ◽  
Meiry Gláucia Freire Rodrigues
Keyword(s):  
Soybean Oil ◽  
Molecular Sieves ◽  
Infrared Region ◽  
Transesterification Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Biodiesel Synthesis ◽  
Autogenous Pressure ◽  
Conversion Parameter

Molecular sieves have been applied to the triacylglycerides processing in the production of biodiesel through transesterification reaction. The purpose of obtain a material that has characteristics favorable to higher biodiesel conversion, this paper aims to synthesize molecular sieves SBA-15 and Al-SBA-15 on two reasons Si/Al (Si/Al= 10 and 100) evaluated in the transesterification reaction of soybean oil and investigate the potential of Si/Al ratios in the reaction over the acid each material. The catalysts were prepared by conventional hydrothermal method by varying the composition of the aluminum consequently altering the acidity of the material, since this reaction takes place in acid medium. The samples were characterized by X-Ray Diffraction (XRD), scanning electron microscopy (SEM), Spectroscopy in the infrared region by Fourier transform (FTIR). The results of the characterization of the catalysts have shown that the materials were successfully obtained, from the characterization observed. The biodiesel syntheses were conducted with soybean oil using ethyl alcohol 12: 1 relative to the oil and 5% of catalyst in the reactor with autogenous pressure. Were realized viscosity analyzes as conversion parameter of the vegetable oil into biodiesel. From the results of biodiesel viscosity was obtained a yield of 13% on average by using the Al-SBA-15. However, even not have remained within the specifications the standards of the National Petroleum, Natural Gas and Biofuels, catalysts showed efficiency compared with the SBA-15 in biodiesel synthesis.

Characterization of aluminophosphates: Identification of 18-member ring structure in AlPO4-8

1990 ◽  
Vol 48 (4) ◽  
pp. 292-293
Author(s):  
J. Ulan ◽  
R. Szostak ◽  
R. Gronsky
Keyword(s):  
Powder Diffraction ◽  
Molecular Sieves ◽  
Molecular Sieve ◽  
Pore Diameter ◽  
Oil Industry ◽  
Theoretical Models ◽  
Ring Structure ◽  
X Ray ◽  
Adsorption Data

The first claim in 1987 of an aluminophosphate (VPI-5) with a pore diameter greater than 7 Å regenerated interest in ultra-large pore molecular sieves for which theoretical models have existed since 1969. Large micropore materials are needed, especially in the oil industry, as catalysts which have the high acidity of zeolites, are thermally stable at high temperatures and pressures, and have significant porosity to allow diffusion of heavier feedstocks currently being seen in refineries.The aluminophosphate VPI-5 is reported to be the first molecular sieve to contain an 18-member ring structure with a pore diameter greater than 12 Å based on X-ray powder diffraction and adsorption data. Researchers at Mobil laboratories have crystallized the silicoaluminophosphate molecular sieve MCM-9 an its X-ray powder diffraction pattern has been shown to match a mixture of VPI-5 and AIPO4-11.

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