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the sulfate anion from water under normal atmospheric conditions (not under an inert atmosphere) using synthetic hydrotalcite prepared by the co-precipitation method. Experimental procedure Preparation of Mg 6 Al 2

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Abstract  

A radiometric procedure for the determination of sulfate based upon the precipitation of barium sulfate is described with a sensitivity of about 0.01 μg/ml. Carrier-free35SO4 is added to the sample to measure the chemical recovery. The sulfate is precipitated with an excess of barium having a known specific activity of133Ba. The amount of133Ba determined by gamma counting is directly related by stoichiometry to the amount of sulfate in the precipitate.

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Orvosi Hetilap
Authors: Krisztián Bácsi, János Kósa, Áron Lazáry, Henrik Horváth, Bernadett Balla, Péter Lakatos, and Gábor Speer

Barrett-Connor, E., Ferrara, A.: Dehydroepiandrosterone, dehydroepiandrosterone sulfate, obesity, waist-hip ratio, and noninsulin-dependent diabetes in postmenopausal women: the Rancho Bernardo

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]. Lanthanides form a series of compounds with properties that change regularly with increasing atomic number of lanthanide. Among many oxysalts, the sulfates hydrates are easily obtained as well-grown crystals from aqueous solutions. Most of the salts are

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Introduction Zirconium sulfate, a catalyst with the characteristics of low cost, easy processing and low toxicity, is usually supported on various carriers in order to improve the catalyst properties. For example, zirconium

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Reaction Kinetics, Mechanisms and Catalysis
Authors: Cleanio L. Lima, Hélvio S. A. de Sousa, Santiago J. S. Vasconcelos, Josué M. Filho, Alcemira C. Oliveira, Francisco F. de Sousa, and Alcineia C. Oliveira

Introduction Sulfatation is a well-known method for increasing the acidity of catalysts by improving their performance in catalytic reactions [ 1 – 8 ]. The promotion of oxides, such as Al 2 O 3, HfO 2 , ZrO 2 , TiO 2 , and Fe

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The thermal decomposition of mercury(I) and (II) sulfates has been investigated by thermogravimetry. The solid-state decomposition products have been characterized by infrared and Raman spectroscopy, mass spectrometry and an X-ray diffraction method. It is concluded that mercury(I) sulfate decomposes in two steps, initially forming a mixture of metallic mercury and mercury(II) sulfate — the latter subsequently decomposes without forming a stable intermediate. The stoichiometry of disproportionation of mercury(I) sulfate and the thermal stability range of mercury(I) and mercury(II) sulfates have been established.

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, and SiO 2 than the natural limestone. These impurities have possibly important effects on the sulfation behavior of the white mud. Laursen et al. [ 18 , 19 ] found that the addition of alkali metal ions improved the sulfur capture capacity of

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Abstract  

The high concentrations of hydrogen sulfide found in many oil and gas fields is thought to arise from the oxidation of petroleum hydrocarbons by sulfate—a reaction that reduces the value of the resource. This review, undertaken in order to better understand the geochemistry of TSR reaction in oil field sediments, covers the relevant information on thermochemical sulfate reduction (TSR) to 1991. The theoretical and experimental aspects of TSR reactions (including sulfur and carbon isotope studies) are reviewed and their significance to the geochemical system discussed. The present review agrees with previous suggestions that biochemical reduction of sulfate dominates in sedimentary environments below 120°C, and supports the possibility that reactive sulfur species will oxidize certain organic molecules at meaningful rates in geochemically reasonable reaction periods at temperatures above 175°C. We conclude that under typical petroleum reservoir reaction conditions, both elemental sulfur and polysulfides are capable of oxidizing some organic molecules under basic conditions. But that sulfate alone will not react unless lower oxidation state sulfur is present. The possible interaction of low-valence-state sulfur with sulfate to form TSR active oxidants is examined. both H2S and SO 4 2− are required for the formation of active polysufide reductants (e.g. thiosulfate or polythionates) in TSR systems. Such intermediates can serve to lower the overall activation energy of the oxidation of hydrocarbons by sulfate via thermal generation of sulfur radicals that can function as TSR active oxidants in many oil field sediments. We suggest that some proposed chemical mechanisms for TSR need to be experimentally verified and the results re-interpreted with respect to TSR relations in geologic systems.

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sulfate. Nagoya J. Med. Sci., 2010, 72 , 1–11. Niwa T. Uremic toxicity of indoxyl sulfate Nagoya J. Med. Sci. 2010

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