Open Access
Photocatalytic degradation of trimethoprim on doped Ti-pillared montmorillonite
(Elsevier, 2019) González, Beatriz; Trujillano, Raquel; Vicente, Miguel Ángel; Rives, Vicente; Korili, Sophia A.; Gil Bravo, Antonio; Institute for Advanced Materials and Mathematics - INAMAT2
Montmorillonite pillared with titanium and doped with Cr3+ or Fe3+ has been tested for the photo-degradation of the antibiotic trimethoprim (trimethoxybenzyl-2,4-pyrimidinediamine) under different conditions, namely, in the dark or in UV light, with or without catalyst, finding excellent catalytic performance under photocatalytic conditions. The degradation by-products were preliminary analysed by mass spectrometry. The results suggested that the molecule broke in two halves, corresponding to its two existing rings. The process continued with the breakage of new fragments from the trimethoxybenzene half, these fragments later reacted with the methoxy groups in this part of the molecule, giving species with m/z values higher than that for the starting molecule, and with the breakage of new fragments.
Open Access
Effective degradation of methylene blue in aqueous solution using Pd-supported Cu-doped Ti-pillared montmorillonite catalyst
(Elsevier, 2019) Joseph, Annu; Vellayan, Kannan; González, Beatriz; Vicente, Miguel Ángel; Gil Bravo, Antonio; Institute for Advanced Materials and Mathematics - INAMAT2
The effluents from the textile, paper and food industries contain organic dyes that are strongly colored and reveal harmful effect on living systems. In order to reduce water pollution, the degradation of dye into non toxic form is desirable. Methylene blue is one such organic dye, discharged from textile industries. In this work, the catalytic degradation of methylene blue was investigated using a montmorillonite supported trimetallic catalyst, prepared by supporting Pd on a Cu-doped Ti pillared montmorillonite. The catalyst exhibited excellent performance to reduce methylene blue, in the presence of NaBH4. The decolorization was appreciable and the results indicated that methylene blue could be successfully decolorized and degraded using the catalyst under room conditions. Almost complete degradation was achieved within 20 min. The results obtained were better than those reported for other catalysts. © 2018 Elsevier B.V.
Open Access
Multifunctional heterogeneous catalysts: Tetrakis (pentafluorophenyl)porphinato]iron(III) immobilized on amine-functionalized Diatomaceous Earth for catalytic and adsorption applications
(Elsevier, 2023) Do Prado, Marcus Vinicius; González, Beatriz; Vicente, Miguel Ángel; Trujillano, Raquel; Nassar, Eduardo José; Gil Bravo, Antonio; Santamaría Arana, Leticia; Korili, Sophia A.; Marçal, Liziane; Faria, Emerson H. de; Ciuffi, Katia J.; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The use of Diatomaceous Earth (DE) as a promising support of a synthetic metalloporphyrin is reported, trying to heterogenize metalloporphyrin catalysts to mimicking enzyme site isolation and improving reaction selectivity. New multifunctional hybrid materials consisting of DE amino–functionalized with aminopropyltriethoxysilane (DE–APTES), followed by grafting with [meso–tetrakis(pentafluorophenyl)porphinato]iron(III) (DE–APTES–FeTFPP), were prepared and fully characterized. FeTFPP was grafted into DE–APTES via the amine groups (band at 1570 cm–1 ). The brown color of the materials indicated that FeTFPP was immobilized in the matrix; a Soret band characteristic of ironporphyrin located in a confined space, was found at 416 nm. Leaching studies confirmed that the ironporphyrin was entrapped and not just adsorbed on the silica surface. DE was composed of typical quartz and cristobalite crystalline phases and amorphous silica. The intensity of its characteristic reflection at 22◦ (2θ) decreased in the presence of FeTFPP, evidencing that the ironporphyrin influenced the organization of the material. Catalytic tests using DE–APTES–FeTFPP in cyclooctene epoxidation to cyclooctene oxide (56 % yield, with complete selectivity for the epoxide) and cyclohexane oxidation (4 % yield of oxidized products, with ketone/alcohol selectivity ~ 3:1), evidenced the versatility of the catalyst and the multifunctionality of the resulting hybrid materials and the ability of DE as a promising natural support for ironporphyrin catalysts. Finally, the capacity of the materials as CO2 adsorbents was evaluated in the temperature range 100–200 ◦C. DE–APTES showed a maximum adsorption capacity of 1.26 mmol/g at 100 ◦C, 18 times higher than the value found under the same conditions for the non–functionalized support.
Open Access
Microwave-assisted pillaring of a montmorillonite with al-polycations in concentrated media
(MDPI, 2017) González, Beatriz; Pérez, Alba Helena; Trujillano, Raquel; Gil Bravo, Antonio; Vicente, Miguel Ángel; Química Aplicada; Kimika Aplikatua
A montmorillonite has been intercalated with Al3+ polycations, using concentrated solutions and clay mineral dispersions. The reaction has been assisted by microwave radiation, yielding new intercalated solids and leading to Al-pillared solids after their calcination at 500 °C. The solids were characterized by elemental chemical analysis, X-ray diffraction, FTIR spectroscopy, thermal analyses, and nitrogen adsorption. The evolution of the properties of the materials was discussed as a function of the preparation conditions. Microwave treatment for 2.5 min provided correctly pillared solids.

Gil Bravo, Antonio

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