Estudo da síntese da zeólita MCM-71

A new kind of material, denominated MCM-71, was synthesized and characterized by several complementary techniques: X Ray Diffractometry, textural analysis by nitrogen adsorption, Scanning electronic microscopy and infrared spectroscopy. MCM-71 zeolite was successfully synthesized by hydrothermal synthesis in the presence of triethanolamine. Mordenite phase as impurity was not detected, otherwise quartz was observed. The MCM-71 sample obtained presented a BET surface area of 20 m²/g in the as synthesized form and of 85 m²/g in protonic form. By SEM was observed crystals with rectangular shape with average size of 2 x 0,2 x 0,05 µm and this crystals were agglomerated in spherical particles with average diameter between 14 and 24 µm

Caracterização de argilas bentonitas e diatomitas e sua aplicação como adsorventes

Five samples of natural clays denominated: diatomite, CN-20, CN-29, CN-40 and CN-45 from Aliança Latina LTDA were characterized by differents supplementary techniques such as: XRD, chemical analysis, adsorption N2 measurements, infrared spectroscopy analysis, thermogravimetric analysis. Clays were tested in adsorption of blue methylene. All of isotherms adjust in a model of physics adsorption with formation of multilayers, however in the case of diatomite was a favorable adsorption (type II) and the CNs were a not favorable adsorption (type III). In the case of CNs had flocculation of clay in high concentration of coloring

Estudo da adsorção de compostos sulfurados empregando zeólitas contendo zinco

This paper deals with an adosrption of sulphur compounds employing zeolites containing zinc. The zeolites employed were commercial NaY and Beta. The zinc was incorporated in three levels: 0.5; 1.0 and 5%. The sulphur compounds studied were benzothiophene and dibenzothiofene. The results showed that both zeolites can be employed for adsorption of benzothiophene and dibenzothiophene. The Zn incorporation (0.5%) promotes an increase in zeolites adsorption ability. The DBT adsorbs more than BT, probably because it strongly interacts with zeolite structure. The BT adsorbs more in NaY than in beta probably because the NaY zeolite has a high intern volume. This is not observed for DBT

Tratamento de águas com excesso de ânions fluoreto e nitrato utilizando HDLs como adsorventes

O objetivo principal do projeto foi buscar um adsorventeefetivo para a remoção de nitratos e fluoretos de águaspara consumo humano. Foi construído um filtro a base deleito fixo para ser utilizado em águas de poços artesianos,beneficiando diretamente a população. Para atingir estesobjetivos, inicialmente se realizou um screening de diversosadsorventes a base de HDLs, argilas e zeóitas para avaliarquais materiais são mais adequados para a remoção denitratos e fluoretos. Os materiais mais promissores foramos HDLs e os mesmos foram empregados em um leito fixoe amostras reais. Os melhores resultados foram obtidos parao HDL com tamanho de partícula acima de 1mm e comvazão de água abaixo de 0,2 mL/s. O filtro é empregado com30g de HDL e consegue-se água potável durante 10h de usocontinuo (equivalente a 4L de água tratada). O adsorventepode ser regenerado através de calcinação a 450oC e tratamentoácido com HCl. Esta metodologia foi desenvolvidana forma de filtros de fácil construção caseira para seremusados em poços da região ou uso doméstico.Fil: Pergher, Sibele B. C.. Universidade Federal do Rio Grande do Norte; BrasilFil: Cano, Leonardo Andres. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Barros Eustaquio, Hugo Mozer. Universidade Federal do Rio Grande do Norte; BrasilFil: Araujo da Costa, Vilma. Universidade Federal do Rio Grande do Norte; BrasilFil: Santos Borba, Loiva Liana. Universidade Federal do Rio Grande do Norte; BrasilFil: Oliveira da Silva, Anne Priscila. Universidade Federal do Rio Grande do Norte; BrasilFil: Garcia Penha, Fabio. Universidade Federal do Rio Grande do Norte; BrasilFil: Martinez Huitle, Carlos Alberto. Universidade Federal do Rio Grande do Norte; BrasilFil: Dallago, Rogerio Marcos. Universidade Federal do Rio Grande do Norte; Brasi

Materiales laminares pilareados: preparación y propiedades

The structure of several types of layered materials will be described. These include clays, layered double hydroxides, group IV metal phosphates and other layered materials. The preparation of the pillared materials and pillaring agents will be presented along with a description of the properties and applications of the products

Preparación y caracterización de la zeolita MCM-22 y de su precursor laminar

The layered precursor of MCM-22 was prepared with different Si/Al ratios: 15, 25, 50, 100 and ¥. Upon heat treatment these precursors form MCM-22 zeolite. Both layered precursor and MCM-22 zeolite were characterized by several techniques: Chemical Analysis by Atomic Absorption Spectroscopy (AAS), X-Ray Diffraction (XRD), Thermo-gravimetric Analysis (TGA), Pore Analysis by N2 and Ar adsorption, Scanning Electron Microscopy (SEM), Infrared Spectroscopy (IR) and Temperature Programmed Desorption of ammonium (TPD)