Liliane Andrade Lima

SBA-15 Molecular Sieve Using Clay as Silicon Sources

New sources of silica as a replacement for TEOS in the synthesis of SBA-15 are been performed by various research teams worldwide. The aim of this work is to describe the synthesis and characterization of SBA-15 made with chocolate B clay as an alternative source of silica by the hydrothermal method. Samples of classic SBA-15 were made with the traditional TEOS method. The samples of the two silica sources were characterized by DRX, EDX, and BET to evaluate the effects of the silica source on the synthesis of the molecular sieve. The chocolate B clay was efficient in the formation of the molecular sieve structure, but there was a great reduction in the surface area and total pore volume in comparison to the surface area of classic SBA-15.

Preparation and Characterization of Catalysts Fe/SBA-15 for Fischer Tropsch Synthesis

In this study catalysts Fe/SBA-15 were prepared for Fischer-Tropsch Synthesis. SBA-15 samples were synthesized under acidic conditions using triblock copolymer Pluronic as a template and tetraethyl orthosilicate as a silica source.The molar composition was: 1.0 TEOS: 0017 P123: 8.14 HCl: 168 H2O. Fe/SBA-15 catalysts with different iron loading (15 wt. % and 20 wt. %) were prepared by wetness impregnation of relative SBA-15 with the desired amount of aqueous iron nitrate. The obtained catalyst were characterized by X ray diffraction (XDR), nitrogen adsorption-desorption and energy dispersive X-ray spectrometry (EDX). After impregnation of Fe the XRD profiles were almost unchanged and exhibited the high diffraction peaks of SBA-15 at low angles. The analysis of nitrogen adsorption-desorption was observed that the values of specific surface area decreased as the concentration of metal impregnated increased. And by the EDX analysis verified that the iron contents obtained are close to nominal levels of iron.

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

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.

Use Residue of Bagasse Sugar Canein Synthesis of Molecular Sieve MCM-41

A mesoporous molecular sieve MCM-41 dimensional hexagonal arrangement has a diameter of 2-10 nm, thermal stability, high pore volume and high surface area. In the synthesis of MCM-41 is used as the CTMABr directing agent and tetraethyl orthosilicate (TEOS) as silica source. Several studies have been developed using the residue of bagasse sugar cane, due to the high percentage of silica in its composition, making it a promising source for materials synthesis, favoring the use of this product impactful to the environment. This paper aims at the synthesis and characterization of MCM-41 with molar composition: 1.0 CTMABr: 4.0 SiO2: 1 Na2O: 200 H2O using waste. The materials were characterized by the techniques of X-ray Diffraction (XRD), chemical analysis by X-ray spectrometry, energy dispersive (EDX) spectroscopy and in the infrared (IR). ). By XRD and IR verified the formation of mesoporous molecular sieve MCM-41. The XRD of the as-synthesized samples MCM-41 displayed the characteristic (1 0 0) reflection of typical MCM-41, with EDX was observed high silica content in the residue of bagasse sugar cane.

Influence of Crystallization Time on Structural and Morphological Characteristics the Precursor of Zeolite MCM-22

In this work the layered precursor of zeolite MCM-22 was synthesized as per the hydrothermal synthesis method, the length of crystallization varying from 8 to 9 days. The preparation of the lamellar precursor of MCM-22 zeolite broke the hydrogels with the following molar composition: 0.511 SiO2: 0.039 NaOH: 0.024 Al2O3: 23.06 H2O. The hydrothermal crystallization occurred in a preheated oven at 150 °C for different periods of 8-9 days. The originality of the work consists in the synthesis of lamellar precursor of MCM-22 zeolite with a variation in the crystallization time from 8 to 9 days, since the literature is used longer times. The materials were characterized by X-ray diffraction (XRD), chemical analysis by atomic energy dispersive X-ray (EDX) and scanning electron microscopy (SEM). The achievement conversion the precursor of MCM-22 zeolite was confirmed by diffracting X-ray, indicating that these materials are crystalline, with typical properties of the samples free of amorphous materials and also that the material became more crystalline as the crystallization increased. From the micrographs, it was observed that the lamellar precursor of MCM-22 zeolite consist of clusters of particles of spherical shape.

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

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.