نتایج جستجو برای: pentasil zeolites
تعداد نتایج: 4917 فیلتر نتایج به سال:
Zeolites have been increasingly used in various application areas such as industry, agriculture, environmental protection, and even medicine. Although, there are no certain figures on the total amount of these minerals the world, some countries e.g. Cuba, USA, Russia, Japan, Italy, South Africa, Hungary and Bulgaria, have important reserves and production potentials. According to reports of 200...
Zeolites Na-A and Na-X are important synthetic zeolites widely used for separation and adsorption in industry. It is of great significance to develop energy-efficient routines that can synthesize zeolites Na-A and Na-X from low-cost raw materials. Coal fly ash (CFA) is the major residue from the combustion of coal and biomass containing more than 85% SiO2 and Al2O3, which can readily replace th...
OBJECTIVES In this research, zeolite X and zeolite Y were used as vehicle to prepare intestine targeted oral delivery systems of indomethacin and ibuprofen. MATERIALS AND METHODS A soaking procedure was implemented to encapsulate indomethacin or ibuprofen within synthetic zeolites. Gravimetric methods and IR spectra of prepared formulations were used to assess drug loading efficiencies into z...
Article type: Original article Objective(s): In this research, zeolite X and zeolite Y were used as vehicle to prepare intestine targeted oral delivery systems of indomethacin and ibuprofen. Materials and Methods: A soaking procedure was implemented to encapsulate indomethacin or ibuprofen within synthetic zeolites. Gravimetric methods and IR spectra of prepared formulations were used to assess...
Hierarchical clinoptilolite and L zeolites are prepared using optimized tandem dealumination-desilication treatments. The main challenge in the post-synthetic modification of these zeolites is the high Al content, requiring a tailored dealumination prior to the desilication step. For natural clinoptilolite sequential acid treatments using aqueous HCl solutions were applied, while for L a contro...
The etherification of glycerol with tert-butyl alcohol in the liquid phase, over different sulfonic acid functionalized zeolites, has been studied. The reaction was carried out using microwaves as a way of heating, measured at autogenous pressure and without any solvent. Dealuminated HY and HZSM-5 zeolites by acid treatment were functionalized with two different organosilica precursors: 3-merca...
The gas-phase carbonylation of dimethoxymethane (DMM) to form methyl methoxyacetate (MMAc) can be catalyzed by acid zeolites. This reaction is a critical step in the synthesis of monoethylene glycol (MEG), a widely used chemical, from synthesis gas. The mechanism of DMM carbonylation occurring on H-MFI and H-FAU zeolites has been investigated using density functional theory. We find that the re...
(1) Background: The tomato leafminer Tuta absoluta (Lepidoptera: Gelechiidae) is a key tomato insect pest. At present, it is considered to be a serious threat in various countries in Europe, North Africa, and Middle East. The extensive use and the developed resistance of T. absoluta to spinosad causes some concern, which leads to the need for alternative products. (2) Materials and Methods: Sev...
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