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[en] The present article deals with investigation of gamma - irradiated petrole samples by means of FT-IR spectroscopy. The transformation of irradiated hydrocarbons takes play in the presence of bentonite. It was discovered that after irradiation of crude oil from Gunesli fields with bentonite it takes play isomerization of hydrocarbons.
[en] The equilibrium isotherms of zinc adsorption onto natural bentonite show that the data correlate well with freundlich and Langmuir's models and that the adsorption is physical in nature. The operating parameters (agitation speed, solid/liquid ratio temperature, particle size and initial zinc concentration) influenced the rate of adsorption. The maximum monomolecular capacity (Q0) according to the Langmuir model is 52.91 mg. g-1 for an initial zinc concentration of 300 mg. litre-1, At 200C
[en] Plate shaped bentonite particles of size ∼600 nm and thickness ∼2 nm are dispersed in a magnetic nanofluid. Magnetic field dependent flow behavior of this composite suspension is studied using a horizontal microcapillary placed between the poles of an electromagnet. The plate shaped bentonite particle produces extra hindrance to the flow under the application of moderate magnetic field and produces an enhanced magnetoviscous effect. 75% volume concentration of bentonite produces eight times larger change in magnetic field dependent viscosity than does the pure magnetic nanofluid. Hindrance to the flow is due to the chain like structure of magnetic nanoparticles, tumbling and rotational motion of bentonite particles and interaction between magnetic and bentonite particles. The field-induced structures are also observed using an optical microscope. Results offer several advantages over the inverse MR effect as well as to study the motion of biological cells and tissues under the effect of magnetic field. -- Highlights: ► Dispersed plate shaped bentonite particles in magnetic fluids to study capillary viscosity. ► Increased viscosity is due to the hindrance to the rotation of the bentonite particles. ► Increase in viscosity is five times larger for bentonite particles than the pure magnetic fluids. ► This is a new kind of magnetoviscous effect, dispersing anisotropic particles in magnetic fluids
[en] Increasing the level of ionizing radiation has a negative effect on human life. Compliance with the basic principles determines the safety of the environment in its original form. Taking into account the fact of the wide use of natural aluminosilicates, in particular bentonite clays, in industry and everyday life, it was of scientific and practical interest to study the distribution of radioactive elements in them. A number of bentonite clays selected from various deposits of the Azerbaijan Republic has been analyzed.
[en] Bentonite has been considered as a candidate buffer material in the underground repository for the disposal of high-level radioactive waste because of its low permeability, high sorption capacity, self sealing characteristics, and durability in nature. The water uptake from the rock and the associated swelling causes a penetration of the bentonite into open fractures, the front of the advancing clay being characteristically very soft. Knowledge of the potential extent of colloid generation is required to estimate the required stability for disposal borehole buffer material and to estimate the potential influence of bentonite colloid on radionuclide transport in deep geological media. It has been recently shown that bentonite colloids can be generated at the host rock/buffer interface of such repositories. Bentonite colloids may constitute an additional mechanism for radionuclide migration toward the geosphere and biosphere, provided they are stable. In this study, therefore, the potential for generation of bentonite colloids caused by the groundwater erosion and the resulting bentonite colloids was studies experimentally for a Korean Ca-bentonite under repository relevant conditions
[en] In this study, modified bentonite was used as man-made barrier systems to investigate occurring reactions with interaction of 79''Se with barrier material systems to protect the environment from radioactive contamination. Thermodynamic parameters of interaction between dominant ion species of selenium and modified bentonite depend on contact time were investigated. In the interaction between modified bentonite and selenium, enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG) were found to have different behaviours depending on the contact time. The adsorption enthalpy increases the duration of the endothermic reaction to the exothermic reaction one hour after the transition and endothermic reaction occurs after two hours.
[en] The adsorption of Cs on clayey materials such as bentonite and Na-montmorillonite was studied in various electrolytic conditions (concentration and composition), various solid to liquid ratios and various pH conditions. The results obtained for these different conditions were modeled considering an exchange model associated to the surface complexation concept. Then, the same approach was considered to model the sorption of Rb, which have the same chemical behavior than Cs. Experiments were carried out for various electrolyte, pH, and Rb concentrations. The stoichiometries corresponding to the sorption of Rb on bentonite and montmorillonite were then deduced from the experimental results. (author)
[en] Adsorption of uranium contained in industrial phosphoric acid has been carried out by batch. The industrial phosphoric acid and the bentonite have been previously caracterized. Theorical models of Langmuir and Freundlich have been applied to the equilibrium isotherm of uranium adsorption to represent the experimental results
[en] A project study for the final disposal of high-level radioactive wastes in deep geological formations, carried out on behalf of Nagra has shown that bentonite could serve as backfilling and sealing material for the final repository concept foreseen by Nagra. Subsequently, the Institute for Foundation and Ground Mechanics of the ETH-Zurich was charged by Nagra with the investigation of various bentonites. The investigations concentrated on the Na-bentonite MX-80 from Wyoming, which is favoured by the Swedes, and on the geographically more favourable Ca-bentonite Montigel from Bavaria. The mineral composition, surface, exchange capacity and exchangeable ions, charge distribution and density of both bentonites have been investigated
[en] Na bentonite is the active component of one of the engineered barriers that are being considered in Sweden to surround the final disposal sites of radioactive wastes from nuclear reactors. It has been chosen because of its low permeability and ion diffusivity and of its self-healing ability through swelling. These properties are due to mineral-water interactions that yield a microstructural pattern with very narrow passages and a low average mobility of interparticle water molecules at high bulk densities