نتایج جستجو برای: 5 zeolite
تعداد نتایج: 1223307 فیلتر نتایج به سال:
The downscaling of feature sizes in integrated circuits (IC) requires on-chip interconnects with low dielectric constant layers (low-k) that mitigate the increase in propagation delay and power consumption. Several candidate low-k materials based on porous silicates have been proposed. Whereas porosity is beneficial for lowering the dielectric constant, it has detrimental effects on the mechani...
In this article, the sorption process of Cr, As and V as oxoanions using modified mordenite zeolite as sorbent has been experimentally estimated. The sample of mordenite zeolite was synthesized and modified and batch method was employed for analysis. Parameters such as sorbent dose, concentration of metal oxoanions in solution ranging from 50 to 5 μg/l and effect of contact time were studied. E...
Lactic acid is an important platform molecule in the synthesis of a wide range of chemicals. However, in aqueous solutions without alkali, its efficient preparation via the direct catalysis of sugars is hindered by a side dehydration reaction to 5-hydroxymethylfurfural due to Brønsted acid, which originates from organic acids. Herein, we report that a previously unappreciated combination of com...
Polyurethane/zeolite 13X nanocomposite films were fabricated using solution casting method. The synthesized nanocomposite films were structurally characterized using SEM, TGA and tensile analysis. SEM images showed appropriate distribution of nanocrystalline zeolite particles within polyurethane matrix. Better thermal stability of nanocomposite films in comparison to neat polyurethane was shown...
We report the one-step synthesis of a highly active hierarchical Fe/ZSM-5 zeolite catalyst with a strongly improved lifetime in the selective hydroxylation of benzene to phenol with nitrous oxide; compared to the best Fe/ZSM-5 catalyst, the turnover number after 24 h on stream is almost four times higher.
An Investigation of the Behavior of Completely Siliceous Zeolite ZSM-5 under High External Pressures
Zeolites are microporous aluminosilicates with well-defined channels and cavities. They have been widely used as ionexchangers, molecular sieves, sorbents, and catalysts. The stability of zeolites is crucial to their applications. Many experimental and theoretical studies have been concentrated on their thermal stability. On the contrary, their behavior under external high pressures has receive...
In order to study the effect of natural zeolite superabsorbent on yield and yield components of linseed under different moisture regimes, a split plot experiment was conducted in a randomized complete block design with 3 replications at Research Farm of Shahrekord University, Shahrekord, Iran in 2017. The main factor in four moisture regimes included irrigation after 50 (control), 80, 130 and 1...
The preparation of responsive multilayered structures with quarter-wave design based on layer-by-layer deposition of sol-gel derived Nb(2)O(5) films and spin-coated MEL type zeolite is demonstrated. The refractive indices (n) and thicknesses (d) of the layers are determined using non-linear curve fitting of the measured reflectance spectra. Besides, the surface and cross-sectional features of t...
The production of aromatic hydrocarbons from cellulose by zeolite-catalyzed fast pyrolysis involves a complex reaction network sensitive to the zeolite structure, crystallinity, elemental composition, porosity, and acidity. The interplay of these parameters under the reaction conditions represents a major roadblock that has hampered significant improvement in catalyst design for over a decade. ...
Zeolite pellets containing 5 wt % of binder (methylcellulose or sodium metasilicate) were formed with a hydraulic press. This paper describes a mathematical model to predict the mechanical properties (uniaxial and diametric compression) of these pellets for arbitrary dimensions (height and diameter) using a design of experiments (DOE) methodology. A second-degree polynomial equation including i...
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