نتایج جستجو برای: mesopore
تعداد نتایج: 405 فیلتر نتایج به سال:
In this work, we propose an improvement of the classical Derjaguin-Broekhoff-de Boer (DBdB) theory for capillary condensation/evaporation in mesoporous systems. The primary idea of this improvement is to employ the Gibbs-Tolman-Koenig-Buff equation to predict the surface tension changes in mesopores. In addition, the statistical film thickness (so-called t-curve) evaluated accurately on the bas...
Separation of gold nanoparticles with a monolithic silica capillary column in liquid chromatography.
A separation system for gold nanoparticles was developed using monolithic silica capillary columns with 50 µm i.d., which were prepared via in-situ sol-gel processes. Gold nanoparticles with five different average sizes were synthesized via reduction of tetrachloroauric acid (HAuCl(4)) under different synthesis conditions, and were evaluated by UV-visible spectrophotometry, dynamic light scatte...
The use of NMR spin-lattice relaxation experiments on water, or other proton-containing fluids, in a porous solid as a pore structure/size measurement tool has been recently reported for porous solids with pore size greater than ~ 5 nm. This approach has numerous advantages, as compared to nitrogen sorption/ condensation and mercury porosimetry, including no network/percolation effects, no pore...
Hollow mesoporous silica particles (HMSPs) have recently drawn much attention as nanocatalysts, owing to their benefits and potential for greener chemical processes. Here, improved synthesis of HMSPs exhibiting a shell with 3-D pore structure is proposed overcome previous synthetic issues, such reproducibility, particle size distribution, precise tailoring size/shell thickness, low yield, etc. ...
A particular type of mesopore extrudates gamma alumina was prepared; which is used as the catalyst in the heavy oil desulfurization unit. Extrudates gamma-alumina support has been made of the boehmite powder from Nephlinsinite mine ores (Surface Area (S.A.) >200 m2/g, Pore Volume (P.V.) =0.48 cm3/g, Average Pore Diameter (A.P.D.) = 8.10 nm); then, many samples of extru...
Carbon molecular sieves were prepared from petroleum coke by chemical activation. The effects of activation temperature, holding time, preliminary treatments and activated agent ratio on surface area, pore structure of the carbon molecular sieves produced in our lab were investigated. The specific surface area and average pore size of the carbon are obviously increased with increasing use of ac...
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