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Copper(II)imida-salen complexes encapsulated into NaY zeolite for oxidations re...

Oxidation of phenol, cychohexanol and hydroquinone has been screened in the presence of copper(II) complexes with Schiff base Salen ligand, 1,5-bis{[(1E)-(2-hydroxyphenyl)methylene]amino}-1H-imidazole-4-carbonitrile, and encapsulated in the zeolite NaY using two different methods (A and B). The new heterogeneous catalysts were characterized by SEM, XRD, FTIR, EPR, Raman and chemical analysis. The structure of t...

Zeolite structures loading with an anticancer compound as drug delivery systems

The authors are thankful to Dr. A. S. Azevedo for collecting the powder diffraction data. ; Two different structures of zeolites, faujasite (FAU) and Linde type A (LTA), were studied to investigate their suitability for drug delivery systems (DDS). The zeolites in the sodium form (NaY and NaA) were used as hosts for encapsulation of α-cyano-4- hydroxycinnamic acid (CHC). CHC, an experimental anticancer drug, w...

Improved biosorption for Cr(VI) reduction and removal by Arthrobacter viscosus ...

The aim of the present work was to optimize the reduction and removal of chromium from aqueous solutions by a biosorption system consisting of a bacteria supported on a zeolite. The system proposed combines the biosorption properties of Arthrobacter viscosus, with the ion exchange capacity of NaY zeolite. Experiments were also performed without the zeolite for comparison purposes. Experimental parameters such a...

Electrocatalytic oxidation of oxalic and oxamic acids in aqueous media at carbo...

The electrochemical oxidation of oxalic and oxamic acids on multiwalled carbon nanotubes (CNT) and on monometallic (Pd and Pt) and bimetallic (Pd-Cu, Pt-Cu) catalysts supported on multiwalled carbon nanotubes was investigated using cyclic voltammetry. The electrodes were prepared by dispersion of the catalytic material on Toray carbon (CT) using a Nafion/water solution. The kinetic parameters of the reactions w...

Science image in Portugal : studying high school students

In the development of activities for the dissemination of science and scientific work there are difficulties and challenges. People get in touch with science in different contexts, as in their workplace or their social life. However, it is in school that the largest number of interaction activities occurs, through communication and education practices. And high school is probably a key context to the promotion ...

Evaluation of ion exchange-modified Y and ZSM5 zeolites in Cr(VI) biosorption a...

The aim of this work is the evaluation of the performance of two zeolites with different structures (FAU and MFI) and acidity properties in the biosorption of Cr(VI) and catalytic oxidation of ethyl acetate. The starting zeolites, Y (FAU) and ZSM5 (MFI), were modified by ion exchange treatments with NaNO3 in order to obtain zeolites with different acidity and sodium content. A biosorption system consisting of a...

Nanocatalysts prepared by encapsulation of manganese(III) complex into NaY zeolite

Actividades experimentais nas escolas através de uma interacção com a universidade

A forma como a ciência é ensinada nas escolas afecta profundamente a percepção que os estudantes têm do mundo que os rodeia e consequentemente a escolha de uma futura carreira nas ciências. Por outro lado, a abertura da escola à comunidade envolvente, proporciona as condições para a sua participação activa na vida escolar, assim como a promoção do sucesso escolar, através da formação integral dos alunos, dotand...

Reutilization of Cr-Y zeolite obtained by biosorption in the catalytic oxidatio...

This work aims at the reutilization of a Cr-loaded NaY zeolite obtained by biorecovery of chromium from water as catalyst in the oxidation of volatile organic compounds (VOC). Cr-NaY catalysts were obtained after biosorption of Cr(VI) using a bacterium, Arthrobacter viscosus, supported on the zeolite. The biosorption experiments were conducted at different pH values in the range 1–4. The catalysts were characte...

Effect of the supporting zeolite structure on Cr biosorption : performance of a...

This work presents a study on the applicability of a zeolite-biomass system to the entrapment of metallic ions, starting from Cr(VI) solutions up to 100 mgCr/L, in batch processes. The effect of the zeolitic support on the overall system performance was evaluated comparing two large pore zeolitic structures which differ in chemical composition and ion-exchange capacity: Faujasite (HY and NaY) and Mordenite (HMO...