نتایج جستجو برای: mercury free catalyst
تعداد نتایج: 593654 فیلتر نتایج به سال:
The palladium nanoparticles were immobilized on DNA-modified multi walled carbon nanotubes as stable and powerful heterogeneous catalyst. The catalyst was characterized by FT-IR spectroscopy, UV-Vis spectroscopy, field emission scanning electron microscopy, X-ray diffraction, transmission electron microscopy, inductively coupled plasma and elemental analysis. DNA as a well-defined structure and...
the present study aimed to use a method for the synthesis of some 3, 4-dihydropyrimidin-2-(1h) - ones/thiones. the study tried to answer the question whether this reaction can be performed without solvent and with new catalyst or not. to find answer to the question, we described a novel protocol for the efficient synthesis of 3, 4-dihydropyrimidin-2-(1h)-one derivatives using aromatic aldehyde,...
Bacteria resistant to methylmercury utilize two enzymes (MerA and MerB) to degrade methylmercury to the less toxic elemental mercury. The crucial step is the cleavage of the carbon-mercury bond of methylmercury by the organomercurial lyase (MerB). In this study, we determined high resolution crystal structures of MerB in both the free (1.76-A resolution) and mercury-bound (1.64-A resolution) st...
in this paper, 4,4ʹ-bipyridinium dichloride supported sba-15 (sba@bipy2+ 2cl-) was used for the synthesis of dihydropyrimidinones. the synthesized catalyst was characterized by ft-ir spectroscopy, scanning electron microscopy (sem), transmission electron microscopy (tem) and thermogravimetric analysis (tga). this nanocomposite was shown to be an efficient heterogeneous catalyst for the synthes...
sulfonated polystyrene/montmorillonite nanocomposite (ommt/ps-so3h) was prepared and used as a novel, efficient and inexpensive heterogeneous acid catalyst in the one-pot reaction three-component mannich reaction of ketones, aromatic aldehydes and amines under solvent-free conditions. the catalyst was characterized by xrd, sem, tg, bet and ft-ir techniques. this method has advantages of high yi...
Introduction The major anthropogenic sources of mercury emission are coal combustion and municipal waste incineration. However, it is very difficult to remove the mercury compounds, particularly elemental mercury vapor, which is not effectively captured in typical air – pollution control devices. It has been reported that activated carbon, particularly activated carbon impregnated with sulfur, ...
The photocatalytic degradation of Procion blue H-B dye in biodegraded textile washwater has been investigated for the complete removal of color and maximum reduction of chemical oxygen demand (COD). Pseudomonas putida was utilized for obtaining biodegraded textile washwater. In this process, silver-doped TiO2 photocatalyst was prepared and experiments were carried out to study the effects of UV...
BACKGROUND Mercury is a pervasive environmental pollutant whose toxic effects have not been studied in sea turtles in spite of their threatened status and evidence of immunosuppression in diseased populations. OBJECTIVES In the present study we investigate mercury toxicity in loggerhead sea turtles (Caretta caretta) by examining trends between blood mercury concentrations and various health p...
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