Showing papers in "Applied Clay Science in 1995"

TL;DR: Clay has always played a major role in human life as discussed by the authors, mainly because of their wide-ranging properties, high resistance to atmospheric conditions, geochemical purity, easy access to their deposits near the earth's surface and low price.

TL;DR: In this article, the surface area of bentonites can only be calculated with methylene blue adsorption when the montmorillonite surface area per charge corresponds with the area of the methylene-blue cation of 130 A 2, i.e. the interlayer charge of the Montmorillonites must amount to 0.28-0.33 charges per half unit cell.

TL;DR: A palygorskite from Bercimuel (Segovia, Spain) was treated with 1.0, 3.0 and 5.0 N solutions of HCI for 1 hour under reflux as discussed by the authors.

TL;DR: In this paper, both the raw and calcined illite samples, before and after being mixed with Ca(OH) 2 in the presence of simulated cement pore solution, were studied by DTA, TG (for raw illite), XRD, SEM, EMPA and chemical solubility.

TL;DR: In this article, the experimental results of adsorption of two phenols (trichlorophenol, TCP, and trinitrophenol, TNP) on an hydrotalcite (HT) and its calcined product (HT500) were summarized.

TL;DR: In this article, the adsorption/desorption behavior of Cd, Cu, Pb, Zn and Ni on illite, beidellite and montmorillonite was investigated using a multichamber device.

TL;DR: In this paper, the effect of initial water contents, initial dry unit weight and soil type on the results of the two most commonly used methods are the zero swell test and the swell-consolidation test is investigated.

TL;DR: In this paper, pyroaurite was synthesized by oxidation of Fe(II) with air in magnesium nitrate solutions at different pH and using different rates of oxidation and the morphology and crystal size of the precipitates vary as a function of x and hydrothermal treatment following precipitation.

TL;DR: In this article, a structural model for the reduction of high surface area Ni/Mg/Al mixed oxides is proposed, based on XRD data, TPR profiles and values of the apparent activation energy of the reduction reaction (before and after NaOH treatment).

TL;DR: In this paper, the acidity and catalytic activity of SAz-1 and JP were investigated by X-ray fluorescence, XRD, thermogravimetry (TG), infrared (IR) spectroscopy, and Si-29 MAS NMR analysis.

TL;DR: In this paper, the interactions between montmorillonite and Zn 2+ and Pb 2+ solutions of different ionic strengths (from about 10 −5 to 1 M) are studied in order to observe changes in the clay-solution system and mineral crystal chemistry.

TL;DR: In this paper, two samples of kaolinite of differing crystallinity have been fired at three temperatures (1260°C, 1500°C and 1600°C) in an air, argon or nitrogen atmosphere XRD analysis of these calcined samples indicates that the content and the cristallinity of cristobalite and orthorhombic mullite depend on two parameters: the crystallinity of the raw material and, at a lesser extent, the firing atmosphere.

TL;DR: In this article, anionic clays Zn2Cr(OH)6C1·2H2O, denoted [ZnCrCI], and Zn3A1(O)8C 1·2HO 2 O, are rapidly exchanged with electroactive organic sulfonate anion such as 2,2′-azinobis 3-ethylbenzothiazoline-6-sulfonate (ABTS), and pillar-like layered structures are formed.

TL;DR: In this article, a review of the use of layered double hydroxides (LDHs) intercalation compounds as catalysts for selected organic chemical conversions is presented. But the authors focus on simple anion exchanged forms of LDHs, whereas others exhibit acid/base character as revealed by the catalytic conversions of 2-methyl-3-butyn-2-ol as a probe molecule.

TL;DR: In this article, the reducibility properties of several anionic clays with the hydrotalcite or takovite structure containing transition metal cations, and of the products (usually a mixture of rock-salt type oxides and spinels) thereof obtained by calcination were investigated.

TL;DR: In this article, a large number of pillared HT anionic clays were synthesized and performed a catalytic study on a large variety of heteropolyoxometalates having the Keggin structure.

TL;DR: Two types of aluminium-phosphate-sulfate minerals are described for the first time from the Lohrheim kaolinitic clay deposit which was laid down during the Tertiary on Devonian rocks of the Rheinisches Schiefergebirge as discussed by the authors.

TL;DR: In this paper, a variety of layered double hydroxides (LDHs) after calcination at 450°C have been used in the aldol condensation reaction of acetaldehyde.

TL;DR: Swelling tests using an environmental scanning electron microscope (ESEM) have been carried out on bentonite of Carboniferous age from the Radzionkow coal mine, Poland as mentioned in this paper.

TL;DR: In this paper, anionic clays, also referred as lamellar-double hydroxides (LDHs), are well known to display a high ionic conductivity for a large variety of interlamellar anionic species.

TL;DR: In this paper, the decolourizing capacity of an acid pedogenic halloysite-rich clay from the Bay of Islands, which had been further acidified to pH 1.5, closely matched that of Tonsil Optimum FF, a standard acid-activated clay based on montmorillonite.

TL;DR: The adsorption of Ni(II) ammine complexes from aqueous solutions onto γ-alumina at neutral pH (pH = 7.2) and ambient temperature has been investigated by X-ray diffraction, EXAFS, transmission and analytical electron microscopy as mentioned in this paper.

TL;DR: In this paper, the synthesis of anionic clays is discussed in terms of the following parameters: nature and properties of both amorphous precursor and crystallization agent, pH of suspension, crystallization temperature, pressure and period of the hydrothermal treatment.

TL;DR: In this paper, a modified capillary wick lysimeters were permanently installed in the vadose zone in an experimental subcatchment under native eucalyptus vegetation at Mount Crawford near Adelaide, South Australia.

TL;DR: In this article, carbonization between the layers of hydrotalcite leads to a formation of highly microporous carbons without additional activation processes, and the structural and surface properties of the template carbons were compared to carbon prepared from the same organic precursor using a conventional carbonization method.

TL;DR: In this paper, the effect of different cation composition on the properties, stability and phase composition of the hydroxycarbonate precursors is discussed, and the thermal decomposition of the brucite-like layers giving some kind of oxycarbonates.

TL;DR: In this paper, the mobilisation and transfer of copper and lead from polluted soil (sample taken from the vicinity of copper smelter) to five different competing sorbents have been studied using a multichamber device.

TL;DR: In this article, structural modifications arising from the treatment were studied by several techniques, including XRD, FTIR, XPS, SEM and porosimetry, and it was shown that the zeolite crystals have been split along the a-axis as a result of the treatment.

TL;DR: Porous clay-organic composites have been prepared by lyophylization of mixtures of clay and organic sols as discussed by the authors, and they are shown to have properties applicable for packing and for use as insulating buffer material.

TL;DR: In this paper, the preparation and characterization of four oligovanadate-pillared hydrotalcite-type layered materials are reported, which are expected to be shape-selective oxidation catalysts with tunable acid-base character.