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En el presente trabajo se estudia la reactividad química de los cationes Fe (III) y W (VI) en disolución acuosa, además se proponen los mecanismos de reacción involucrados en el proceso químico hasta la obtención de la fase sólida. Las reacciones químicas involucradas en medio acuoso fueron estudiadas usando el Modelo de Carga Parcial (MCP) que describe la hidrólisis y condensación de los cationes Fe (III) y W(VI) disueltas en agua y las especies químicas que forman al enlazarse con ligandos H2O,OH y O2 . La polimerización sol-gel, así como la formación de la fase sólida hasta la obtención del óxido de hierro y óxido de tungsteno fueron estudiadas por las técnicas de Espectrofotometría Visible, Dispersión de Luz, Espectroscopia Infrarroja, Microscopía Electrónica por Transmisión y Difracción de Rayos X. Se determinó que las fases sólidas del W(VI) y Fe (III) a ...

In the present work we studied the chemical reactivity of cations Fe (III) and W (VI) in watery dissolution ,besides we propose the involved mechanism of reaction in thechemical process until the obtaining of the solid phase. The chemical reactions involved in the middle watery were studied using the Model of Charge Partial (MCP) whodescribes to the hydrolysis and condensation of cations Fe(III) and W(VI) dissolved in water and the chemical species that form when connecting with links H,O, OH and0₂. The polymerization sol-gel, as well as the formation of the solid phase until the obtaining of oxide of iron and tungsten oxide were studied by the techniques of VisibleSpectroscopy, Dispersion of Light, Infrared Spectroscopy, Transmission Electronic Microscopy and X-ray Diffraction. It were determined that the solid phases of the W(VI) and Fe (III) to 500 °C were monoclinic WO, and a-Fe.O...

Enzymatic catalysis is a sustainable alternative for cost-prohibitive catalysts based on noble metals and rare earths. Enzymes can catalyze selective reactions under mild conditions. Enzyme recovery after a reaction for its reuse is still a challenge for industrial application. Herein, a biocompatible magnetic nanocomposite is presented as alternative for enzyme stabilization and easy recovery. The magnetic core of CoFe2O4 provides capabilities for magnetic recovery. Two different functionalization methods based on adsorption of enzyme onto biocompatible hydroxyapatite (HAP) and through covalent bonding using a molecular spacer based on 3-Aminopropyl)triethoxysilane (APTES) have been evaluated. Both enzymatic bio-nanocomposites presented high selectivity for the transesterification reaction of racemic mixtures of (R,S)-1-phenylethanol, with complete conversion of (R)-1-phenylethanol enan...

Nanowire/nanorod TiO2 structures of approximately 8 nm in diameter and around 1,000 nm long were synthesized by alkaline hydrothermal treatment of two different TiO2 nanopowders.

Multiple discs coated with hierarchically-organized TiO2 anatase nanotubes served as photoelectrodes in a novel annular photoelectrocatalytic reactor. Electrochemical characterization showed light irradiation enhanced the current response due to photogeneration of charge carriers. The pharmaceutical acetaminophen was used as a representative water micropollutant. The photoelectrocatalysis pseudo-first-order rate constant for acetaminophen was seven orders of magnitude greater than electrocatalytic treatment. Compared against photocatalysis alone, our photoelectrocatalytic reactor at <8 V reduced by two fold, the electric energy per order (EEO; kWh m-3 order-1 for 90% pollutant degradation). Applying a cell potential higher than 8 V detrimentally increased EEO. Acetaminophen was degraded across a range of initial concentrations, but absorbance at higher concentration diminished photon ...

Photoelectrocatalytic (PEC) water treatment is a promising technology for organic pollution abatement. Much of the prior research focused on material discovery and optimization. However, challenges exist in scaling-up PEC processes and are associated with designing reactors with effective light irradiation on electrode surfaces and, simultaneously, efficient electrode configurations. We design and demonstrate key reactor design principles, which influence reaction mechanisms, for a reactor using a TiO2 nanotube-coated disc flow reactor. Degradation of organochlorinated 2,4-dichlorophenol was studied as representative carcinogenic micropollutant. The synergistic photoelectrocatalytic process showed 5-fold faster degradation kinetics than solely electrocatalytic treatment or a greater than 2-fold enhancement over photocatalysis alone. Applicability of photoelectrocatalytic treatment was de...

Gold nanoparticles (Au NPs) have been widely employed in catalysis. Here, we report on the synthesis and catalytic evaluation of a hybrid material composed of Au NPs deposited at the surface of magnetic cobalt ferrite (CoFe2O4). Our reported approach enabled the synthesis of well-defined Au/CoFe2O4 NPs. The Au NPs were uniformly deposited at the surface of the support, displayed spherical shape, and were monodisperse in size. Their catalytic performance was investigated towards the reduction of 4-nitrophenol and the selective oxidation of dimethylphenylsilane to dimethylphenylsilanol. The material was active towards both transformations. In addition, the LSPR excitation in Au NPs could be employed to enhance the catalytic performance, which was demonstrated in the 4-nitrophenol reduction. Finally, the magnetic support allowed for the easy recovery and reuse of the Au/CoFe2O4 NPs. In this...