Silica

Ordered (SBA-15) and disordered (KIL-2) mesoporous silica supports have been synthesized and used for incorporation of titania with different Ti/Si molar ratios (1/2, 1/1, 2/1) via sol–gel impregnation method. Titanium isopropoxide and aqueous titania sol prepared by low-temperature sol–gel processing were used as a source of titania. Characterization by powder X-ray diffraction (XRD), nitrogen sorption measurements, scanning electron microscopy (SEM) and UV–vis–NIR diffuse reflectance spectroscopy (DRS) has been carried out to investigate the chemical framework and morphology of powders. The photocatalytic degradation of isopropanol in the gaseous medium was selected as a probe reaction to test the photoactivity of powders and to verify the potential application of these materials for air remediation. It was found that the titania source, Ti/Si molar ratio and the type of silica support influenced the functional properties of the material, which were evaluated by adsorption capacity and photocatalytic activity in the gas–solid reactor. The adsorption capacity of isopropanol was the highest in the presence of the SBA-15-supported materials. The photoactivity results indicated that the powders which were prepared using SBA-15 as a silica support and a Ti/Si molar ratio of 1/1 were the most active towards isopropanol oxidation monitored in situ by FT-IR spectroscopy.

The present manuscript describes a biomarker capturing strategy based on nanoporous silica particles. The method is shown to enrich the yield of species in the low-molecular weight proteome (LMWP), allowing detection of small peptides in the low-nanomolar range. Plasma samples were exposed to the silica particles, and the captured molecular species were profiled using MALDI-TOF. Mass spectra of the silica-treated human plasma samples showed a significant enrichment in MALDI-TOF protein profiles in the LMWP. Preliminary results indicated good level of reproducibility in plasma profiles with CVs on peak heights ranging from 6.3 to 14.7%. The MALDI-TOF signature changed significantly when the characteristics of the nanoporous silica were altered. The facile sample pretreatment before MS analysis, coupled to the potential for tailoring the surface properties of silica supports, hold promise for improving the recovery of low-abundance serum biomarkers.

1414 Bull. Korean Chem. Soc. 2004, Vol. 25, No. 9 ... Nitration of Aromatic Compounds on Silica Sulfuric Acid ... Mohammad Ali Zolfigol,†,* BiBi Fatemeh Mirjalili,‡ Abdolhamid Bamoniri, Mohammad Ali Karimi Zarchi, Amin Zarei, Leila Khazdooz, and Jalil Noei ... †Chemistry Department, ...

In order to examine the associations between sinonasal cancer and occupational exposures other than wood dust and leather dust, the data from 12 case-control studies conducted in seven countries were pooled and reanalyzed. The pooled data set included 195 adenocarcinoma cases (169 men and 26 women), 432 squamous cell carcinomas (330 men and 102 women), and 3136 controls (2349 men and 787 women). Occupational exposures to formaldehyde, silica dust, textile dust, coal dust, flour dust, asbestos, and man-made vitreous fibers were assessed with a job-exposure matrix. Odds ratios (ORs) were adjusted for age, study, wood dust, and leather dust, or other occupational exposures when relevant. 95% confidence intervals (CIs) were estimated by unconditional logistic regression. A significantly increased risk of adenocarcinoma was associated with exposure to formaldehyde. The ORs for the highest level of exposure were 3.0 (Cl = 1.5-5.7) among men and 6.2 (CI=2.0-19.7) among women. An elevated r...

Nanometric Fe2O3 particles could be inserted inside the internal pore volume of SBA-15 mesoporous silica and mesoporous alumina supports, when Fe(III) chelates (EDTA, gluconate or citrate) were used as impregnating precursors. The oxidative degradation of the chelating anions was followed by combined TG-DTA. Strong chelate-SiOH interactions (case of bulky EDTA), favored by the mesopore curvature, yield sub-nanometric extremely well dispersed Fe2O3 particles preferentially located at the micropore mouths (confinement effect). Fe2O3 even more strongly interacts with alumina walls, generating either (Fe,Al)2O3 mixed phases or Fe-aluminate micro domains. These iron-based mesoporous alumina composites proved very active catalysts in total oxidation of phenol at ambient conditions, with extremely low iron leaching (0.2%).