Search results for " mesoporous"
showing 9 items of 19 documents
Very high titanium content mesoporous silicas
2001
Titanium content in mesoporous titanosilicate catalysts has been modulated up to a minimum Si/Ti value of 1.9 by using complexing agents able to coordinate both Si and Ti atoms and harmonize the reactivity of the resulting precursors avoiding subsequent phase segregation and leading to chemically very homogeneous materials. El Haskouri, Jamal, Jamal.Haskouri@uv.es ; Beltran Porter, Aurelio, Aurelio.Beltran@uv.es ; Beltran Porter, Daniel, Daniel.Beltran@uv.es ; Amoros del Toro, Pedro Jose, Pedro.Amoros@uv.es
Efficient boron removal by using mesoporous matrices grafted with saccharides.
2004
Highly efficient boron removal from water was achieved by using mesoporous silica materials functionalised with saccharides. Beltran Porter, Daniel, Daniel.Beltran@uv.es ; Amoros del Toro, Pedro Jose, Pedro.Amoros@uv.es
Functional Magnetic Mesoporous Silica Microparticles Capped with an Azo-Derivative: A Promising Colon Drug Delivery Device
2018
[EN] Magnetic micro-sized mesoporous silica particles were used for the preparation of a gated material able to release an entrapped cargo in the presence of an azo-reducing agent and, to some extent, at acidic pH. The magnetic mesoporous microparticles were loaded with safranin O and the external surface was functionalized with an azo derivative 1 (bearing a carbamate linkage) yielding solid S1. Aqueous suspensions of S1 at pH 7.4 showed negligible safranin O release due to the presence of the bulky azo derivative attached onto the external surface of the inorganic scaffold. However, in the presence of sodium dithionite (azoreductive agent), a remarkable safranin O delivery was observed. A…
Aging of MCM41, MSU-H and MSU-F mesoporous systems investigated through the Raman spectroscopy
2014
Here we report an experimental investigation, based on the Raman spectroscopy, on the aging of some mesoporous silica based systems. In details, we studied the aging in air of the MCM41, the MSU-H and the MSU-F materials by acquiring the Raman spectra of as received and of mechanically pressed, at 0.2 and 0.45 GPa, powders. Our data evidenced that the starting powders of the MCM41 and of the MSU-H undergo structural modification when they are exposed to the ambient atmosphere, such modification consisting in the decrease of the D2 Raman band (originated by the three member rings). At variance the powders of the MSU-F appear to be stable. Furthermore, by pressing the starting powders to prod…
Caspase 3 Targeted Cargo Delivery in Apoptotic Cells Using Capped Mesoporous Silica Nanoparticles
2015
[EN] Excessive apoptotic cell death is at the origin of several pathologies, such as degenerative disorders, stroke or ischemia-reperfusion damage. In this context, strategies to improve inhibition of apoptosis and other types of cell death are of interest and may represent a pharmacological opportunity for the treatment of cell-death-related disorders. In this scenario new peptide-containing delivery systems (solids S1-P1and S1-P2) are described based on meso-porous silica nanoparticles (MSNs) loaded with a dye and capped with the KKGDEVDKKARDEVDK (P1) peptide that contains two repeats of the DEVD target sequence that are selectively hydrolyzed by caspase3 (C3). This enzyme plays a central…
Nanosensor for Sensitive Detection of the New Psychedelic Drug 25I-NBOMe.
2020
[EN] This work reports the synthesis, characterization, and sensing behavior of a hybrid nanodevice for the detection of the potent abuse drug 25I-NBOMe. The system is based on mesoporous silica nanoparticles, loaded with a fluorescent dye, functionalized with a serotonin derivative and capped with the 5-HT2A receptor antibody. In the presence of 25I-NBOMe the capping antibody is displaced, leading to pore opening and rhodamine B release. This delivery was ascribed to 5-HT2A receptor antibody detachment from the surface due to its stronger coordination with 25I-NBOMe present in the solution. The prepared nanodevice allowed the sensitive (limit of detection of 0.6 mm) and selective recogniti…
Interaction of Gold with Co-Condensed and Grafted HMS-SH Silica: A 29Si {1H} CP-MAS NMR Spectroscopy, XRD, XPS and Au LIII EXAFS Study
2010
Hexagonal mesoporous silica (HMS) is functionalised with mercaptopropyl groups by adopting two different procedures ; co-condensation and grafting. In both cases tetraethylorthosilicate (TEOS) and 3-mercaptopropyltriethoxysilane (3-MPTES) are used as the silicon and sulfur precursors, respectively. The obtained materials are analysed by several techniques such as N 2 sorption, TG-DTA, XRD, SAXS and-solid state 29 Si { 1 H} CP-MAS NMR spectroscopy. By taking advantage of the chemical interaction between gold and the -SH groups, the effect of the thiol addition procedure on the supporting capability of the functionalised silica is evaluated by depositing gold through the incipient wet impregn…
MCM-41 silica effect on gel polymer electrolytes based on thermoplastic polyurethane
2012
Abstract Polymer electrolytes were prepared from thermoplastic polyurethane with addition of mixture of N-ethyl(methylether)-N-methylpyrrolidinium trifluoromethanesulfonimide (PYRA12O1TFSI) ionic liquid, lithium bis(trifluoromethanesulfoneimide) salt and propylene carbonate. MCM-41 mesoporous silica was added in proportions ranging from 5 to 20 wt.% with respect to TPU. The electrolytes were characterized by thermogravimetric analysis, differential scanning calorimetry, linear voltammetry and impedance spectroscopy. The MCM-41 addition to the system was found to improve the electrochemical stability of the membranes and to reduce the gel electrolyte/metallic Li interfacial resistance. The f…
Carbons from second generation biomass as sustainable supports for catalytic systems
2018
Abstract In this study activated carbons were produced from the wood of three different wood species (pine, birch, spruce). The resulting activated carbons were characterized in bulk for ash content, carbon content (elemental analyses), specific surface area, and pore size distribution, and at the surface by measuring the autogenerated pH and studying their structure by XPS. All the samples presented high surface areas and appeared to be mesoporous materials (mesopores >80%). The carbons were then used as support for AuPt nanoparticles and tested in the liquid phase oxidation of glycerol (GLY) and in the hydrogenation of levulinic acid (LA), two important chemicals from cellulose-based biom…