Photodegradation of pharmaceutical drugs using Sn-modified TiO2 powders under visible ligth irradiation

Sn-modified TiO2 powders with different amounts of tin (0, 2.4, 5.1 and 7.2 at.%) were obtained by the surfactant-assisted technique using Pluronic P123 as template. The synthesis procedure favors the formation of a mixture anatase/rutile at annealing temperatures as low as 350 C. The incorporation and further increase of the tin content promotes the transformation of anatase to rutile phase allowing to vary the anatase to rutile ratio in a controlled way, reaching the rutile phase the 96% of the mixture at a Sn content of 7.2 at.%. The synthesized materials were tested in the photocatalytic degradation of the NSAIDs, diclofenac, ibuprofen and paracetamol present in real wastewaters to evaluate their catalytic performance under visible light. The obtained results seem to indicate a certain kind of selectivity or affinity for degradation of each specific drug with a catalyst.The authors thank UAEM for the financial support through the project 3458 CHT. Thanks also to the staff of the SIEA-UAEM for their help and technical support. This work was partially supported by CONACYT, under the project CB-168827

FACTORES QUE AFECTAN LA TEXTURA Y ESTRUCTURA DE Ti(R)-MCM-41 FACTORES QUE AFECTAN LA TEXTURA Y ESTRUCTURA DE Ti(R)-MCM-41

<p>Se ha estudiado el efecto que tienen el método de remoción del surfactante y el contenido de titanio sobre la estructura y propiedades texturales de los materiales mesoporosos Ti-MCM-41. Los sólidos sintetizados fueron caracterizados por fisisorción de N2, fluorescencia de rayos X (FRX), difracción de rayos X (DRX), microscopía electrónica de alta resolución (HREM), espectroscopía FT-Raman y de reflectancia difusa UV-vis. (DRS). Entre los dos métodos de remoción del surfactante estudiados, la aplicación de un disolvente polar (solución de H2SO4 0.05 M en etanol) resultó ser más efectivo para remover el surfactante y disminuir la destrucción del material mesoporoso durante la calcinación. Las muestras tratadas con este método presentaron un mayor orden en el arreglo hexagonal de los poros (HREM, DRX) y áreas superficiales más grandes. El efecto del aumento del contenido de TiO2 en los sólidos sintetizados se traduce en una disminución significativa de la intensidad del pico característico de MCM-41 (2Q = 2.2-2.5o) y de las características texturales (SBET, volumen de poros), lo que indica que durante la síntesis no es posible incorporar más de 10 mol. % de TiO2 al MCM-41.</p><br><p>Studied was the effect surfactant removal and titanium content have on the structure and textural properties of Ti-MCM-41 mesoporous materials. The synthesized solids were characterized by N2 adsorption, X-ray fluorescence (FRX), X-ray diffraction (DRX), electronic microscopy of high resolution(HREM), and FT-Raman and UV-vis diffuse reflectance spectroscopy (DRS). Between the two methods of surfactant removal studied, the application of a polar solvent (solution of 0.05 M H2SO4 in ethanol) was to be more effective in removing the surfactant and diminishing the destruction of mesoporous material during calcination. The samples treated by this method showed a more ordered hexagonal pore arrangement (HREM, XRD) and larger surface area. The effect of an increase in TiO2 content in synthesized solids translates itself into a significant decrease of the peak intensity characteristic of Ti- MCM-41 (2È = 2.2-2.5o) and textural properties (SBET pore volume), which indicates that during the synthesis it is not possible to incorporate more than 10 mol. % of TiO2 into the MCM-41 framework.</p

2,3-Diferrocenylcyclopropenone: Synthesis, Structure, and Some Chemical and Electrochemical Properties

Alkylation of ferrocene with tetrachlorocyclopropene in the presence of AlCl3 followed by aqueous workup affords 2,3-diferrocenylcyclopropenone in high yield. We have studied some of this ketone's chemical transformations and electrochemical properties. 2,3-Diferrocenylcyclopropenone withstands thermolysis; it is stable in an acidic medium; the action of tetrafluoroboric acid-diethyl ether results in the formation of diferrocenyl(hydroxy)cyclopropenylium tetrafluoroborate; nucleophiles, including methyllithium and lithium aluminum hydride, react regioselectively with the three-membered ring by opening it to form the respective substituted cis-diferrocenylethenes. We present data from X-ray diffraction analyses of 2,3-diferrocenylcyclopropenone, isopropyl cis-2,3-diferrocenylacrylate, and cis-3,4-diferrocenyl-2-methylbut-3-en-2-ol. © Wiley-VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2003