Herve M. Laborde

Swelling of Brazilian Organoclays in Some Solvents with Application in the Petroleum Industry

Brasgel clay has been modified via cation exchange reaction using quaternary ammonium chlorides (stearyl dimethylammonium chloride, Praepagen). Basal spacing, interlamellar structure clay have been characterized using X-ray diffraction (XRD) technique. The organoclay was characterized by the Foster Swelling test. The results indicated that the quaternary ammonium salts were intercalated between the layers of clay. The Foster Swelling Test results indicated that the affinity of stearyl dimethylammonium chloride, Praepagen occurred in the treated clay tested in all organic solvents (diesel, gasoline, toluene and p-xylene), without and with agitation. the treated sample presented a high swelling capacity (with and without agitation) when tested in gasoline. On the other hand, when inserted in diesel oil without agitation, the treated samples presented low swelling capacity, but when the assay was performed under agitation, it yielded an intermediate swelling capacity. In Toluene, the samples presented intermediate swelling, both without and with agitation. In p-xylene, the samples presented low swelling, without and intermediate swelling, with agitation. Therefore, this clay can be used for the removal of oils and greases from polluted aqueous effluents of the petroleum industry.

Structural and Morphology Characterization ZSM-5 Zeolite by Hydrothermal Synthesis

Zeolite ZSM-5 have been synthesized by hydrothermal method, using tetrapropylammonium bromide as template. This work aims to evaluate the preparation and characterization structural and morphology of zeolite ZSM-5 resulting in a pure and crystalline material. The ZSM-5 zeolite was prepared by hydrothermal synthesis at 170 °C, using silica, deionized water and structure-directing salt (tetrapropylammonium bromide-TPABr). Several techniques like X ray diffraction (XRD), scanning electron microscopy (SEM) and X ray energy dispersion spectrophotometer (EDX) have been utilized to characterize the framework structure and morphology of the sample. Obtaining ZSM-5 zeolite could be confirmed by X ray diffratograms. The result X ray diffraction showed that the synthesized sample presented typical peaks of the ZSM-5 zeolite. According to the XRD, it is possible to observe intense and well defined peaks. The acquired X ray patterns identified the product as highly-crystalline materials, without the presence of impurities. From the images obtained by SEM, it was possible are composed of showed that the crystal accumulations of ZSM-5 zeolite, without the presence secondary phases on the crystals.

Periodic protein adsorption at the gold/biotin aqueous solution interface: evidence of kinetics with time delay.

An oscillatory molecular adsorption pattern of the protein neutravidin from aqueous solution onto gold, in presence of a pre-deposited self assembled mono-molecular biotin film, is reported. Real time surface Plasmon resonance sensing was utilized for evaluation of the adsorption kinetics. Two different fractions were identified: in the initial phase, protein molecules attach irreversibly onto the Biotin ligands beneath towards the jamming limit, forming a neutravidin-biotin fraction. Afterwards, the growth rate exhibits distinct, albeit damped adsorption-desorption oscillations over an extended time span, assigned to a quasi reversibly bound fraction. These findings agree with, and firstly confirm a previously published model, proposing macro-molecular adsorption with time delay. The non-linear dynamic model is applicable to and also resembles non-damped oscillatory binding features of the hetero-catalytic oxidation of carbon monoxide molecules on platinum in the gas phase. An associated surface residence time can be linked to the dynamics and time scale required for self-organization.

Effects of Reduction of Percent of Template (HMI) and Time of Static Synthesis on the Structure of MCM-22 Zeolite

This work aims to study the effects of reducing the level of template HMI (100, 75, 50, 25 and 0% HMI) and time (10, 9 and 8 days) of static synthesis in the structure of MCM-22 zeolite. The synthesis of the MCM-22 (P) precursors was carried out by using hexamethyleneimine (HMI) as organic template under static conditions. The MCM-22 zeolites (100, 75 e 50% HMI) was obtained by the calcination of precursors MCM-22 (P) in a muffle to remove the occluded organic of precursors. These materials were characterized by X-ray diffraction (XRD), spectroscopy of X-ray for energy dispersive (EDX), adsorption isotherms of N2 (BET method), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The XRDs and EDXs of all samples have confirmed the static synthesis of MCM-22, whose precursor and zeolite materials showed all the characteristic peaks of the topology MWW. The Adsorption isotherms of N2 are of type I, represented by microporous materials, whose hysteresis (type H3) are representative of solids with pores of different geometries. The FTIRs shown that the precursors showed the characteristic bands of a laminated material. From the SEMs, it was found the samples calcined MCM-22 are constituted by strip-shaped crystals agglomerated with a depression in the central region. In the sample MCM-22 (P) 75% HMI (8 days), showed no crystals uniform due to the presence of unreacted material in relation to crystalline phases.

Preparation of Zeolite MCM-22 Using the Rice Husk Ash as Silica Source

Brazil is a great producer of rice generating large amounts of husks after rice processing. These hulls contain high percentage of SiO2, and a great potential as raw material for the development of silica based materials, as zeolites. Thus, this work aims to use the silica of rice hulls as an alternative raw material for the production of zeolite MCM-22. This material was characterized through X-ray diffraction, X-ray spectrophotometry and physical adsorption of N2 (BET). The diffraction pattern of precursor MCM-22 presented typical peaks of topology MWW. Calcined sample did not presented peaks related with the organic material used in of the zeolite MCM-22, indicating that the thermal treatment was efficient for organic removal. It was confirmed, through the EDX, that the synthesized materials present high amount of SiO2 and low quantity of Al2O3. The BET isotherms indicated that the materials presented structures with microporous, concluding that the alternative silica was promisingly for the development of zeolites.

Preparation and Characterization of Zeolite ZSM-5 in the Template: Effect of Crystallization Time on the Structure and Textural Properties

The preparation of ZSM-5 templates in the absence of organics is an area of high technological impact. These are responsible for the enhancement of the final products (zeolites). Therefore, the preparation of zeolites in the absence of template allows a compromise covering the low cost and environment. This study aimed to investigate the influence of synthesis time in the preparation of ZSM-5. This zeolite was prepared by hydrothermal synthesis, using as co-template (C2H5OH) and addition of seeds. The times of synthesis used were 3 to 5 days. The solids were characterized by XRD, BET and Spectroscopy in the infrared region. Through the results obtained with XRD, it was observed that all samples showed characteristic peaks of MFI structure of the group at intervals of 2θ = 7-9° and 23-25°, showing no presence of secondary phases. BET surface area showed a corresponding literature. The infrared showed bands characteristic of ZSM-5.