نتایج جستجو برای: clay minerals
تعداد نتایج: 41990 فیلتر نتایج به سال:
Copyright: © 2014 Xiong Li, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Soils are known to be “skin of the earth” and carry the material basis for human beings. As one of the basic disciplines of ag...
The aim of this review is to examine the hypothesis that organic matter decreases the adsorption of radiocaesium on clay minerals. The factors that determine radiocaesium mobility and bioavailability in soil are briefly outlined to show why a relationship between soil organic matter content and enhanced Cs bioavailability is paradoxical. In all the investigations reviewed the ionic compositions...
Cesium adsorption/desorption experiments for various clay minerals, considering actual contamination conditions in Fukushima, were conducted using the (137)Cs radioisotope and an autoradiography using imaging plates (IPs). A 50 μl solution containing 0.185 ~ 1.85 Bq of (137)Cs (10(-11) ~ 10(-9 )molL(-1) of (137)Cs) was dropped onto a substrate where various mineral particles were arranged. It w...
The surface area of the individual phyllosilicates (clay minerals) in Athabasca oil sands determined from XRD crystallite size measurements was found to be comparable to the bulk surface area measured by ethylene glycol monoethyl ether adsorption. The primary phyllosilicates are kaolin and illite but the large surface area is imparted by varying degrees of smectitic interstratifications in the ...
Both Fe(III)-bearing clay minerals and humic acids (HAs) are abundant in the soils and sediments. Previous studies have shown that bioreduction of structural Fe(III) in clay minerals could be accelerated by adding anthraquinone compound as a redox-active surrogate of HAs. However, a quinoid analogue could not reflect the adsorption and complexation properties of HA, and little is known about th...
The Earth's surface comprises minerals diagnostic of weathering, deposition and erosion. The first continental-scale mineral maps generated from an imaging satellite with spectral bands designed to measure clays, quartz and other minerals were released in 2012 for Australia. Here we show how these satellite mineral maps improve our understanding of weathering, erosional and depositional process...
Vold's mathematical analysis of the d.t.a, curve has been applied to Murray's data on the dehydration of clays. Owing to experimental uncertainties, values for the heats of dehydration are lower than those determined by other methods. The first ruder law is obeyed and the activation energies of dehydration are of the same order as those derived from isothermal data; rates of dehydration are, ho...
The effect of orientation of vermiculite particles on the diffusion of Na ion was measured by a tracer technique. The diffusion measurements were made on pellets prepared by pressing freezedried vermiculite in a cylindrical die and the diffusion coefficient evaluated by a thin-film boundary condition of Fick's law. Because flakes of vermiculite were highly oriented under the pressing force, it ...
The use of computational methods for the study of clay minerals has become an essential adjunct to experimental techniques for the analysis of these poorly ordered materials. Although information may be obtained through conventional methods of analysis regarding macroscopic properties of clay minerals, information about the spatial arrangement of molecules within the interlayers is hard to obta...
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