On The Synthesis of Zeolite Y/ZSM-5 Composite via Novel Technique (original) (raw)
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Synthesis of ZSM−5 zeolite using Bayat natural zeolite as silica and alumina source
AIP Conference Proceedings
Zeolite ZSM-5 has been successfully synthesized from natural zeolite Bayat without further purification. The silica and alumina source are taken from the natural zeolite through submolten depolimerization method. Ludox 40% was used as additional silica source to reach Si/Al ratio of 32 in the starting gel and tetrapropylammonium hydroxide (TPAOH) was used as a structure directing agent (SDA). Synthesis was carried out hydrothermally with aging and crystallization temperature at 150°C. The as-synthesized zeolite was characterized with XRD, FTIR and SEM-EDX. The XRD patterns of the resulted synthesis showed diffraction peaks at 2θ = 7.9°-8.8° (doublet peaks) and diffraction peaks at 2θ = 22°-25° (triplet peaks) which are characteristic for ZSM-5 structure. The SEM image showed that the ZSM-5 zeolite from Bayat natural zeolite had morphology of hexagonal crystalls with some debris of impurities. The elemental analysis using EDX gave Si/Al molar ratio of 18.5.
Preparation and characterization of ZSM-5 zeolite
International journal of computational and experimental science and engineering, 2023
The research for new energy sources has promoted hydrocarbon production from biomass and solid wastes over ZSM-5 zeolites. The metal incorporation by different methods has led to a variety of chemical applications. In this way, the combination of the shape selectivity and acidity properties of the pentasil zeolites with the activity of metal oxide under different environments may influence the product distribution in diverse catalytic reactions. In this work, ZSM-5 zeolites were prepared by hydrothermal synthesis employing aluminum nitrate and AIP as aluminium sources and TPAOH as structure director agent at atmospheric pressure and low temperature (90 ºC). In addition, these materials were modified with iron and titanium cations by direct synthesis at 170 °C and autogenous pressure to promote the crystallinity. The characterization of the samples was performed by XRD, XRF, SEM, TPD-NH 3 and nitrogen adsorption. It was observed that the use of AIP and the metal incorporation decreases the crystallinity of the zeolites under synthesis conditions, which leads to increase the specific area value in the BET because of the presence of amorphous material. On the other hand, acidity of the modified zeolites was found to be lower than that of ZSM-5 zeolite.
Powder Technology, 2015
Nanosized ZSM-5 zeolite hexagonal cubic micro-blocks with different Si/Al ratios were successfully synthesized by using TPAOH in the presence of nonionic surfactant (Triton X-100) by a hydrothermal method. The samples prepared with the surfactant were characterized by XRD, XRF, FT-IR, N 2 adsorption, HR-TEM, HR-SEM and NH 3-TPD analysis to evaluate the particle structure, size and acid strength. Pure crystalline phase of ZSM-5 is confirmed by powder X-ray diffraction. FT-IR analysis further showed that nanosized zeolite has double five rings of the MFI-type of typical absorption at about 550 cm-1. The SEM images clearly show that all ZSM-5 zeolite samples possess the similar hexagonal spheres morphology with particle size of about 320-360 nm. The influence of Triton X-100 in the structural, textural, morphological and catalytic properties of ZSM-5 is compared with conventional ZSM-5. The catalytic activity of ZSM-5 zeolites with different Si/Al ratios (ZSM-5-WS(x) and ZSM-5-WOS(x)) is evaluated in the selective oxidation of benzyl alcohol (BzOH) using tert-butyl hydroperoxide (TBHP) as an oxidant and water as a solvent. The Triton X-100-assisted preparation yielded a zeolite exhibiting a higher conversion than the one prepared in the absence of Triton X-100. Among the catalysts, ZSM-5-WS(28) (Si/Al = 28) catalyst exhibited significantly higher conversion at optimum conditions. This catalyst can be retrieved and reprocessed for five times without a significant loss in its activity and selectivity.
Catalysis letters, 2003
In the absence of a structure-directing organic molecule, aluminosilicate ZSM-5 is produced directly from high-silica zeolite Y or zeolite by a simple hydrothermal treatment of the alkali metal hydroxide-treated starting zeolite material. NMR and FTIR results clearly suggest that the majority of the Al(III) species is present in the framework yielding Brønsted acid sites. Addition of an appropriate organic molecule such as tetrapropylammonium bromide or tetrabutylammonium bromide facilitates the formation of ZSM-5 and ZSM-11, respectively. The protonated form of all the ZSM-5 catalysts shows very good catalytic activity for the conversion of methanol to hydrocarbon.
Preparation of ZSM-22 zeolite with hierarchical pore structure
Materials Letters, 2018
ZSM-22 zeolite samples were synthesized with and without the use of trimethoxyphenylsilane in conjunction with nanometric silica beads, producing materials with intracrystalline micro-mesopore structures. Subsequently, the solids were desilicated by varying the NaOH solution concentration. The XRD results indicated that the samples were highly crystalline and the nitrogen adsorption analysis showed that the desilication of the materials with the presence of organosilane caused a greater increase of surface area, external area, mesoporous volume, and higher yields of solid.
Synthesis and characterization of ZSM-5 zeolite from serpentine
Applied Clay Science, 2003
A serpentine mineral was treated in hydrochloric acid solution to obtain amorphous silica with high surface area. The highly porous silica residue was used as a silica source for the synthesis of zeolite ZSM-5 by hydrothermal method. The syntheses were conducted with variations in the composition of aNa 2 OÁbAl 2 O 3 ÁcSiO 2 ÁdH 2 OÁe(TPA) 2 O, the reaction temperature of 125 to 185 jC, and the reaction time of 12 to 48 h. An optimum condition for the synthesis was achieved with a composition of a = 11.7, b = 1, c = 90, d = 3510, and e = 10.8 at 170 jC for 24 h, followed by calcinations at 600 jC. The crystallinity degree of the prepared zeolites was in 90% to 97% and the highest was obtained at SiO 2 /Al 2 O 3 molar ratio of 90 at which its average particle size and surface area were 1.2 Am and 357 m 2 /g, respectively.
International Journal of Technology: IJ Tech, 2022
This article describes the study of synthesis of ZSM-5 Zeolite based on kaolin as catalysts for catalytic cracking of heavy distillate. There are five types of formulas A, B, C, D, and E synthesized with varying the molar ratios of SiO2/Al2O3, SiO2/Na2O, and H2O/SiO2 and characterized by chemical compound, microstructure and catalytic performance. Three methods conducted the catalytic cracking of heavy distillate such as without catalyst, Ni-Mo commercial catalyst, and bifunctional catalyst ZSM-5 from Formula E, which was impregnated with transition metals (Ni, Mo) to be Ni-Mo/HZSM-5. The catalytical performance test result shows that, under operational conditions (~350 C, 1 MPa), middle distillate hydrocarbon is obtained by the catalytic cracking of heavy distillate using Ni-Mo commercial catalyst and Ni-Mo/HZSM-5 Formula E catalyst. When a Ni-Mo/HZSM-5 Formula E catalyst and Ni-Mo Commercial Catalyst were used in the cracking process, a light hydrocarbon fraction (C3-C5) was formed.
Microporous and Mesoporous Materials, 2012
In this work, the influence of alkalinity, A = [Na 2 O/H 2 O] b (b = batch), of the reaction mixture on structural, particulate, morphological and chemical properties of the crystalline end products obtained by hydrothermal treatment (heating at 483 K for 2 h) of the TPA-free reaction mixture: 1.0Al 2 O 3 /100SiO 2 / xNa 2 O/4000H 2 O seeded by silicalite-1 nanocrystals (260 nm, 4 wt.% of silica in gel mixture), was investigated by different characterization methods such as powder X-ray diffraction (XRD), scanning-electron microscopy (SEM), particle size distribution (PSD) measuring by laser light scattering (LLS) and X-ray fluorescence (XRF). The obtained results showed that, when silicalite-1 having the size of 260 nm was used as seed, fully crystalline product (silicalite-1/ZSM-5) having the size in the range of 400-600 nm and Si/Al ratio of 10-18 can be obtained for 0.006 6 A 6 0.01, in less than 2 h. However, the product obtained at low (A 6 0.005) or high (A P 0.011) alkalinities possess amorphous and/or phillipsite impurities, respectively. The influence of alkalinity, A, on the mentioned properties of the crystalline end product was discussed in relation to the influence of alkalinity on the relevant critical process of zeolite ZSMcrystallization in the absence of organic templates.