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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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Abstract  

The objective of this research was to investigate the effect of different clay composition and concentrations on the thermal behaviour and kinetics of heavy crude oil in limestone matrix by thermogravimetry (TG/DTG). In TG/DTG experiments, three distinct reaction regions were identified in all of the crude oil + limestone mixture known as low temperature oxidation (LTO), fuel deposition (FD) and high temperature oxidation (HTO) respectively. Addition of clay to porous matrix significantly affected the reaction regions. Significant reduction of activation energy due to addition of clay to crude oil indicates the catalytic effect of clay on crude oil combustion.

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Abstract  

In this work, Cs+ ion sorption on some clays and zeolite were investigated. 137Cs was used as a tracer. Activities were measured with a NaI crystal gamma counter. The particle size distribution was determined by a laser sizer. Surface area of the particles were determined by BET (Brunauer, Emmett and Teller method). Structure analysis was made by using X-ray diffraction. The chemical compositions of the solid samples were determined using a ICAP-OE spectrometer. Kinetic and thermodynamic parameters were determined. Due to very high uptake results; clay and zeolite can be proposed as a good sorbents in waste management considerations.

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Abstract  

The results of Cr(VI) adsorption on the red clay modified by hexadecyltrimethylammonium bromide are given. The adsorption isotherm of Cr(VI) is determined based on the Langmuir–Freundlich model and exhibits the adsorption capacity of 0.0005 mol/g in relation to Cr(VI). The study of the pH effect showed that the optimal pH range corresponding to the Cr(VI) adsorption maximum on this clay is 2–6.5. Thermal analysis of the modified adsorbent, i.e., Na/HDTMA-clay, shows two DTG peaks at 58–61 and 241 °C. The first one is a consequence of dehydration of the modified clay sample. The other DTG peak results from evaporation and pyrolysis of HDTMA adsorbed on the clay. In the case of Na/HDTMA-Cr-clay three peaks appear at: 64, 232, and 340 °C. The third DTG peak is related to the oxidation of surfactant. Moreover, the raw mineral shows the peak at 543 °C attributed to the clay dehydroxylation.

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Abstract  

In this study, radiocesium sorption on ceramic clay was investigated as a function of particle size and initial 137Cs concentration using a batch method. Ceramic clay samples taken from the Söğüt(İnisar) clay deposit were composed of kaolinite, dickite and quartz. The equilibrium time and the liquid–solid ratio were determined as 60 min and 250 mL g−1, respectively. The distribution coefficients (K d) for variable liquid–solid ratio and the percentage adsorption (P Ad) were calculated. The values of K d and P Ad ranged from 483 to 3165 mL g−1 and 34–93%, respectively. The K d and P Ad values increased with increasing particle size, but decreased with increasing initial concentration. The sorption data were interpreted in terms of a Langmuir isotherm. The results indicated that the Söğüt(İnhisar) ceramic clay has good sorption capacity for cesium.

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Journal of Thermal Analysis and Calorimetry
Authors: Pascal Clausen, Marco Signorelli, Andreas Schreiber, Eric Hughes, Christopher Plummer, Dimitrios Fessas, Alberto Schiraldi, and Jan-Anders Månson

Abstract  

Desorption isotherms for water, ethanol, ethyl acetate and toluene from a sodium smectite clay have been determined by both dynamic vapor sorption (DVS) measurements and Knudsen thermogravimetry (KTGA), at the exception of toluene that was measured only by the DVS method. The results obtained using these two methods were in satisfactory agreement, providing reliable insight into the desorption process, with certain lack of precision for ethyl acetate. The observed desorption behaviour suggests a liquid like phase at high volatile load, and a sorbed state in which molecules interact with the counter ions, at low volatile contents. However, the isotherms for water determined at various temperatures nearly superposed when plotted as a function of water activity, indicating the strength of the interactions in the clay–water system to remain of the same order of magnitude as that in bulk water, consistent with previous ab initio calculations.

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Journal of Thermal Analysis and Calorimetry
Authors: Veridiana Reyes-Zamudio, Carlos Angeles-Chávez, and Jorge Cervantes

deterioration of this kind of stone has been reported [ 4 – 7 ]. One of the main weathering processes is the dissolution of feldspars and volcanic glass and the formation of secondary clay minerals such as halloysite, smectite, illite, allophane, and kaolinite

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-based nanocomposites have been extensively carried out to find their promising alternatives to traditional composites, though they were mainly focused on general mechanical and multifunctional properties and filler dispersion. The clay-containing nanocomposite is one

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– 4 ]. Clay minerals are non-pollutant and have a significant adsorption capacity so they can have a privileged role in the treatment of water [ 5 , 6 ]. Pillaring and acid activation processes are used in order to improve clay properties [ 7 – 12

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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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