Search results for "mesoporous"
showing 8 items of 358 documents
Metallocenes and post-metallocenes immobilized on ionic liquid-modified silica as catalysts for polymerization of ethylene
2014
Abstract The supported ionic liquid (SIL) strategy was used for the first time to metallocene and post-metallocene heterogeneous catalysts for olefin polymerization. The metal complexes: Cp2TiCl2, Cp2ZrCl2, FI–Ti, and Sal–Ti were immobilized in the 1-(3-triethoxysilyl)propyl-3-methylimidazolium alkylchloroaluminate ionic liquid, anchored on the surface of the mesoporous amorphous silica. The SIL systems were characterized by FTIR, 29Si NMR, N2 adsorption, EA, AAS, TG, and SEM techniques. The developed supported catalytic systems were found to be active in the ethylene polymerization and produce the polyethylene of various properties.
Protein recovery as a resource from waste specifically via membrane technology : from waste to wonder
2021
Economic growth and the rapid increase in the world population has led to a greater need for natural resources, which in turn, has put pressure on said resources along with the environment. Water, food, and energy, among other resources, pose a huge challenge. Numerous essential resources, including organic substances and valuable nutrients, can be found in wastewater, and these could be recovered with efficient technologies. Protein recovery from waste streams can provide an alternative resource that could be utilized as animal feed. Membrane separation, adsorption, and microbe-assisted protein recovery have been proposed as technologies that could be used for the aforementioned protein re…
Sorption and mechanism studies of Cu2+, Sr2+ and Pb2+ ions on mesoporous aluminosilicates/zeolite composite sorbents
2020
The research aimed to develop a novel mesoporous aluminosilicate/zeolite composite by the template co-precipitation method. The effect of aluminosilicate (AlSi) and zeolite (NaY) on the basic properties and adsorption capacity of the resultant composite was conducted at different mass ratios of AlSi/NaY (i.e., 5/90, 10/80, 15/85, 20/80, and 50/50). The adsorption characteristics of such composite and its feedstock materials (i.e., aluminosilicates and zeolite) towards radioactive Sr2+ ions and toxic metals (Cu2+ and Pb2+ ions) in aqueous solutions was investigated. Results indicated that BET surface area (SBET), total pore volume (VTotal), and mesopore volume (VMeso) of prepared materials f…
The Influence of Nanoparticle Shape on Protein Corona Formation
2020
Nanoparticles have become an important utility in many areas of medical treatment such as targeted drug and treatment delivery as well as imaging and diagnostics. These advances require a complete understanding of nanoparticles' fate once placed in the body. Upon exposure to blood, proteins adsorb onto the nanoparticles surface and form a protein corona, which determines the particles' biological fate. This study reports on the protein corona formation from blood serum and plasma on spherical and rod‐shaped nanoparticles. These two types of mesoporous silica nanoparticles have identical chemistry, porosity, surface potential, and size in the y ‐dimension, one being a sphere and the other a …
Formation of Si/SiO2 Luminescent Quantum Dots From Mesoporous Silicon by Sodium Tetraborate/Citric Acid Oxidation Treatment
2019
We propose a rapid, one-pot method to generate photoluminescent (PL) mesoporous silicon nanoparticles (PSiNPs). Typically, mesoporous silicon (meso-PSi) films, obtained by electrochemical etching of monocrystalline silicon substrates, do not display strong PL because the silicon nanocrystals (nc-Si) in the skeleton are generally too large to display quantum confinement effects. Here we describe an improved approach to form photoluminescent PSiNPs from meso-PSi by partial oxidation in aqueous sodium borate (borax) solutions. The borax solution acts to simultaneously oxidize the nc-Si surface and to partially dissolve the oxide product. This results in reduction of the size of the nc-Si core …
Voltammetric Detection of Lead(II) Using Amide-Cyclam- Functionalized Silica-Modified Carbon Paste Electrodes
2009
2-(4,8,11-Triscarbamoylmethyl-1,4,8,11-tetraazacyclotetradec-1-yl)acetamide (TETAM) derivatives bearing 1, 2, or 4 silylated arms have been synthesized and grafted to the surface of silica gel and ordered mesoporous silica samples. The resulting organic-inorganic hybrids have been incorporated into carbon paste electrodes and applied to the preconcentration electroanalysis of Pb(II). The attractive recognition properties of these cyclam derivatives functionalized with amide pendent groups toward Pb(II) species and the highly porous structure of the adsorbents can be exploited for the selective and sensitive detection of the target analyte. Various parameters affecting the preconcentration a…
Activated Carbon Production from Peat Using ZnCl2 : Characterization and Applications
2017
The process for producing activated carbon from peat was optimized. The peat was impregnated with different ratios of ZnCl2, and the impregnated biomass was activated at different temperatures. The specific surface area, pore size distribution, total carbon content, and yield of the activated carbon were investigated. The best results for the specific surface area and mesoporosity of the activated peat were obtained by using a high impregnation ratio (2) and high activation temperature (1073 K). Highly porous activated carbon was produced that had a specific surface area of approximately 1000 m2/g and total pore volume that was higher than 0.5 cm3/g for most samples. The activated carbon ha…
Dual Enzyme-Triggered Controlled Release on Capped Nanometric Silica Mesoporous Supports
2012
The development of nanoscopic hybrid materials equipped with “molecular gates” showing the ability of releasing target entrapped guests upon the application of an external trigger has attracted great attention and has been extensively explored during recent years.1 These nanodevices are composed of two subunits, namely, a suitable support and certain capping entities grafted on the surface of the scaffolding.2 The support is used as a suitable reservoir in which certain chemicals can be stored whereas the molecules grafted in the outer surface act as a “gate” and can control the release of the entrapped molecules at will. Both components are carefully selected and arranged in order to achie…