نتایج جستجو برای: na montmorillonite
تعداد نتایج: 269236 فیلتر نتایج به سال:
The present paper reports the successful elaboration of exfoliated plasticized starch-based nanobiocomposites. This was made possible by using cationic starch as a new clay organomodifier to better match the polarity of the matrix and thus to facilitate the clay exfoliation process. To demonstrate the efficiency of this new approach, either natural (MMT-Na) or organomodified (OMMT-CS) montmoril...
Abstraet---Ethylenediamine (EDA) is adsorbed from aqueous solution on Na-, Kand Li-montmorillonite as the monoprotonated cation (EDAH +) through an ion-exchange process. On washing with distilled water the second amine function is protonated--probably through dissocmtion of water near the clay surface--and simultaneously formed alkali hydroxide is removed. In air-dried clay films, prepared from...
The effect of the pristine sodium montmorillonite (Na-MMT) on the styrene emulsion polymerizations with different concentrations of SDS ([SDS]) was investigated. At constant [SDS], the polymerization rate is faster for the run with 1 wt.% Na-MMT compared to the counterpart without Na-MMT. Micelle nucleation predominates in the polymerizations with [SDS] = 13 mM. On the other hand, the contribut...
Among emerging pollutants, endocrine disruptors such as estradiol are of most concern. Conventional water treatment technologies not capable removing this compound from water. This study aims to assess a method that combines physicochemical and biological strategies eliminate even when there other compounds present in the matrix. Na-montmorillonite, Ca-montmorillonite zeolite were used remove m...
Nanoporous sodium montmorillonite clay (Na+-MMT) was used as a support for the immobilization of 1-methyl-3-(trimethoxysilylpropyl)-imidazolium hydrogen sulfate (Na+-MMT-[pmim]HSO4). This catalyst showed excellent catalytic activity for the preparation of 2-amino-3-cyano-5-oxo-5,6,7,8-tetrahydro-4H-benzopyrans via three-component reactions betw...
In this work, a series of hydrogel nanocomposites were prepared by grafting acrylic acid and acrylamide on gelatin in the presence of Na-montmorillonite (Na-MMT) nanoparticles. The characterizations of hydrogel nanocomposites were examined by swelling experiments, Fourier transform infrared (FT-IR) spectroscopy, X-Ray diffraction (XRD) patterns and thermogravimetric analysis (TGA). Scanning ele...
The montmorillonite sample from Heping, China had been studied by chemical analysis, XRD, IR, AFM and MAS NMR. The results showed that acid concentration had much influence on surface structure of montmorillonite. When the acid concentration reached 2M, the Q3Si structure in silica-oxygen tetrahedron recombined, some Q3Si structure in montmorillonite transformed to distortion Q3Si structure and...
Ground pollution arises from the impact of past and current industrial activity and due to improper disposal of waste generated by society. Geoenvironmental engineering deals with the most important aspects: (a) Soil pollution processes and effect on geotechnical properties, and (b) Waste Management. Soil-pollutants interaction changes soil behaviour and also can lead to various geotechnical pr...
This paper performs molecular dynamics simulations to investigate the role of the monovalent cations K, Na and the divalent cation Ca on the stability and swelling of montmorillonite. The recently developed CLAYFF force field is used to predict the basal spacing as a function of the water content in the interlayer. The simulations reproduced the swelling pattern of these montmorillonites, sugge...
Nanoporous sodium montmorillonite clay (Na+-MMT) was used as a support for the immobilization of 1-methyl-3-(trimethoxysilylpropyl)-imidazolium hydrogen sulfate (Na+-MMT-[pmim]HSO4). This catalyst showed excellent catalytic activity for the preparation of 2-amino-3-cyano-5-oxo-5,6,7,8-tetrahydro-4H-benzopyrans via three-component reactions betw...
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