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Journal of Thermal Analysis and Calorimetry
Authors: Yuri Park, Godwin A. Ayoko, Janos Kristof, Erzsébet Horváth, and Ray L. Frost

difficulty has been overcome by introducing cationic surfactant molecules into the interlamellar space, and the properties of clay minerals are enhanced as organoclays. In recent years, organoclays have been used of oil-spill clean-up operations [ 2 – 4

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adsorption of organic compounds by clay minerals is widespread in nature and in industry. Complexes obtained by the adsorption of organic compounds by clay minerals are known as organoclays. In modern technology, organoclay-based nanocomposites obtained by

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Journal of Thermal Analysis and Calorimetry
Authors: Yuri Park, Godwin A. Ayoko, Janos Kristof, Erzsébet Horváth, and Ray L. Frost

exchangeable inorganic cations in the clay minerals with organic cations, modified clay minerals can been prepared and are known as organoclays. These organically modified clays are used in industrial applications such as nanofillers in polymer

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Journal of Thermal Analysis and Calorimetry
Authors: E. Araújo, Renata Barbosa, Crislene Morais, L. Soledade, A. Souza, and Moema Vieira

Abstract  

Nanocomposites containing both polyethylene and montmorillonite clay organically modified with four different types of quaternary ammonium salts were obtained via direct melt intercalation. Thus, the main purpose of this work was to evaluate the effect of the organoclay on the thermal stability of polyethylene. The organoclays were characterized by XRD, FTIR, DSC and TG. The polyethylene/organoclay nanocomposites were studied by XRD, TEM, TG, besides an evaluation of their mechanical properties. The results showed that the salts were incorporated by intercalation between the layers of the organoclay and, apparently that the nanocomposites were more thermally stable than pure polyethylene.

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Summary  

Organoclays are used in cleaning natural waters from dissolved hydrocarbons by secondary sorption. Aiming future applications in this field, a Brazilian polycationic bentonite was used to prepare HDTMA organoclays, by using different quaternary ammonium salt loadings and clay content slips, to evaluate how these conditions may affect their sorption properties. The organoclays were characterized by CHN analysis, X-ray diffraction, thermogravimetry, and differential thermal analysis. For secondary sorption tests, to compare with published studies, toluene was used as a reference sorbate. Characterization and sorption results indicate that the Brazilian bentonite organoclays prepared in this study have a potential industrial use in environmental applications.

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Abstract  

The aim of this work was to compare the influence of organocations with different length of alkylammonium chain on the structural stability of clays towards mechanochemical treatment. An industrial product JP A030 (Envigeo, Inc., Slovakia) based on Jelšový Potok bentonite (Slovakia) and three organoclays prepared from this material via ion exchange with tetramethylammonium, octyltrimethylammonium and octadecyltrimethylammonium cations (TMA-JP A030, OTMA-JP A030 and ODTMA-JP A030, respectively) were ground for 1–20 min in a high-energy planetary mill. The products were investigated by X-ray diffraction analysis, thermal analysis, scanning electron microscopy and energy dispersive X-ray analysis. The long-chain organic cations apparently enhance the structural stability of bentonite during high-energy grinding.

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Journal of Thermal Analysis and Calorimetry
Authors: Marilda Vianna, Jo Dweck, Frank Quina, Flavio Carvalho, and Claudio Nascimento

Abstract  

Commercial bentonite (BFN) and organoclay (WS35), as well as iron oxide/clay composite (Mag_BFN) and iron/oxide organoclay composite (Mag_S35) were prepared for toluene and naphthalene sorption. Mag_BFN and Mag_S35 were obtained, respectively, by the precipitation of iron oxide hydrates onto sodium BFN and S35 clay particles. The materials were characterized by powder X-ray diffraction (XRD), X-ray Fluorescence (XRF), and TG and DTA. From XRF results and TG data on calcined mass basis, a quantitative method was developed to estimate the iron compound contents of the composites, as well as the organic matter content present in WS35 and Mag_S35.

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Journal of Thermal Analysis and Calorimetry
Authors: Z. Yermiyahu, I. Lapides, and S. Yariv

Abstract  

An intense blue organo-clay color pigment was obtained by adding naphthyl-1-ammonium chloride to a Na-montmorillonite aqueous suspension followed by treatment with sodium nitrite. This treatment resulted in the synthesis of the azo dye 4-(1-naphthylazo)-1-naphthylamine adsorbed onto the clay. The pigment was subjected to thermo-XRD-analysis and the diffractograms were curve-fitted. Heating naphthylammonium-montmorillonite at 360°C resulted in the evolution of the amine at temperatures lower than those required for the formation of charcoal and consequently the clay collapsed. On the other hand, heating the pigment at 360°C resulted in the conversion of the adsorbed azo dye into charcoal. The clay did not collapse, thus proving that the azo dye was located inside the interlayer space. Before the thermal treatment a short basal spacing in the pigment compared with that in the ammonium clay (1.28 and 1.35 nm, respectively) indicated stronger surface π interactions between the clayey O-plane and the azo dye than between this plane and naphthylammonium cation. The amount of dye after one aging-day of the synthesis-suspension increased with [NaNO2]/[C10H7NH3] ratio but did not increase with naphthylammonium when the [NaNO2]/[C10H7NH3] ratio remained 1. After 7 and 56 aging days it decreased, indicating that some of the dye decomposed during aging.

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. 87 : 377 – 382 10.1007/s10973-006-7886-6 . 3. Xi , Y , Ding , Z , He , H , Frost , R . 2005 . Infrared spectroscopy of organoclays synthesized with the surfactant

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Journal of Thermal Analysis and Calorimetry
Authors: Marilda Vianna, Jo Dweck, Frank Quina, Flavio Carvalho, and Claudio Nascimento

Abstract  

This study investigates the sorption of toluene and naphthalene by a sodium bentonite (BFN), an organoclay (WS35) and by their respective iron oxide hydrate composites Mag_BFN and Mag_S35. The organic matter content of WS35 and Mag_S35, determined by thermogravimetry, was used to obtain their organic matter sorption coefficients, which show that they are effective sorbents to remove organic contaminants from water, with a higher selectivity for naphthalene than for toluene sorption. The main iron oxide phase present in Mag_BFN and Mag_S35 is maghemite (γ-Fe2O3), which allows these sorbents to be separated from the effluent by a magnetic separation process after use.

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