Influence of organobentonite structure on toluene adsorption from water solution

Vidal, Nuria; Volzone, Cristina

doi:10.1590/s1516-14392012005000126

Cited by 13 publications

(4 citation statements)

References 70 publications

(44 reference statements)

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“…The lengths of C16TMA cations in all trans configurations were in the range of 2.2 nm to 2.5 nm [ 28 , 43 ]. The basal spacing of Na-magadiite completely dehydrated (similar to H-magadiite) was approximately 1.12 nm [ 6 , 28 ].…”

Section: Resultsmentioning

confidence: 99%

Application of Organo-Magadiites for the Removal of Eosin Dye from Aqueous Solutions: Thermal Treatment and Regeneration

et al. 2018

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Na-magadiite exchanged with cetyl-trimethylammonium cations provided organophilic silicate materials that allowed for the effective removal of the acidic dye “eosin”. The organic cations were intercalated into the interlayer spacing of the layered silicate via an exchange reaction between the organic cations from their bromide salt and the solid Na-magadiite at room temperature. Different techniques were used to characterize the effect of the initial concentration of the surfactant on the structure of the organo-magadiites. The C, H, and N analysis indicated that a maximum of organic cations of 0.97 mmol/g was achieved and was accompanied by an expansion of the basal spacing of 3.08 nm, with a tilted angle of 59° to the silicate layers. The conformation of the organic surfactants was probed using solid-state 13C, finding mainly the trans conformation similar to that of the starting cetyl trimethylammonium bromide salt (C16TMABr). Thermal gravimetric analysis was carried out to study the thermal stability of the resulting organo-magadiites. The intercalated surfactants started to decompose at 200 °C, with a mass loss percentage of 8% to 25%, depending on the initial loading of the surfactant, and was accompanied by a decrease of the basal spacing from 3.16 nm to 2.51 nm, as deduced from the in situ X-ray diffraction studies. At temperatures below 220 °C, an expansion of the basal spacing from 3.15 to 3.34 nm occurred. These materials were used as a removal agent for the anionic dye eosin. The maximum amount of the dye removed was related to the organic cation content and to the initial concentration of eosin, with an improvement from 2.5 mg/g to 80.65 mg/g. This value decreased when the organo-magadiite was preheated at temperatures above 200 °C. The regeneration tests indicated that an 85% removal efficiency was maintained after six cycles of use for the organo-magadiite using Ci of 200 mg/L.

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Section: Resultsmentioning

confidence: 99%

Application of Organo-Magadiites for the Removal of Eosin Dye from Aqueous Solutions: Thermal Treatment and Regeneration

et al. 2018

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“…The positively charged ends of the cationic surfactants were exchanged with the interlayer exchangeable cations of the kenyaite (Na + ) and the hydrophobic head of the cationic surfactants was arranged outward (Ahmadishoar et al, 2017). The C16TMA + cations generated an organophilic phase partition in the interlayer spacing, through interaction of the dyes with the cationic C16TMA + cations (Bergaya & Lagaly, 2001; Park et al, 2004; Onal, 2007; Vidal & Volzone, 2012).…”

Section: Removal Of Eosinmentioning

confidence: 99%

Characterization of organo-kenyaites: thermal stability and their effects on eosin removal characteristics

et al. 2018

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Organo-kenyaites were prepared from a cetyltrimethylammonium hydroxide (C16TMAOH) solution and solid sodium kenyaite (Na2Si22O45.10H2O) mixture. The effect of the initial cetyltrimethylammonium solution on the structure of the intercalated materials was investigated by CHN analyses, X-ray diffraction (XRD), thermogravimetric analysis, SEM, and 29Si and 13C solid NMR techniques. For C16TMAOH concentration 0.25 mM, the Na+ cations were fully exchanged. Initial C16TMAOH concentrations higher than 0.25 mM had little effect on the intercalated amount of C16TMA+ cations. The organic cations content reached a plateau of 0.66 mmol/g. The arrangement model of C16TMA+ cations corresponded to a tilt of the organic cations to the silicate layers with an angle of 42° as deduced by XRD studies. The C16TMA+ cations exhibited mainly trans-configuration of the methyl chains, as was shown by solid 13C NMR. The thermal stability of the organo-silicates was studied using in situ FTIR and in situ XRD in the range 25–450°C. The C16TMA-kenyaites were stable at temperatures below 200°C. They collapsed at higher temperatures due to the decomposition of the intercalated surfactants. These organo-kenyaites were used to remove the acidic dye molecule, eosin. The removal tests were performed at varying conditions of initial dye concentrations, organic content in the organo-kenyaites and heating temperatures. In general, the organic modification improved the removal capacity of the Na-kenyaite from 2 mg of eosin/g to 60 mg of eosin/g, and this capacity was related to the organic contents and the calcination temperatures of the organo-kenyaites.

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“…The clay used in this work was a bentonite from the province of San Juan, Argentina. This clay has been characterized in previous works [20] and is composed mainly of montmorillonite, with traces of quartz and feldspar. The structural formula of the montmorillonite clay mineral in this sample is Si 3.94 Al IV 0.06 Al VI 10.36 Fe 0.06 Mg 0.60 O 10 (OH) 2 .…”

Section: Methodsmentioning

confidence: 99%

High-temperature transformations of Zr-pillared bentonite

Martínez

Conconi

Booth

et al. 2020

J Therm Anal Calorim

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A Zr-modified bentonite (B-OHZr) obtained by intercalation of OH-Zr species was obtained, and its thermal transformations at > 800 °C were studied. Raw clay and B-OHZr were characterized by X-ray diffraction, thermogravimetric and differential thermal analysis, and its sintering behavior was studied by hot-stage microscopy. Two Zr-based phases-tetragonal zirconia and zircon-were observed in thermally treated B-OHZr with a sharp decrease in amorphous glassy phase in comparison with the parental clay. An increase in refractoriness was observed in B-OHZr, enabling the sintering of samples up to 1300 °C, while the parental clay bloated and deformed with thermal treatment. The Zr interlayering enhanced the refractoriness at high temperatures of the parental clay, eliminating thermal expansion (bloating) and enabling sintering at T > 1000 °C. The observed features and thermochemical processes enlighten the temperature usage range of these kinds of materials. Finally these results yield promising features for potential use of these clays for the preparation of ceramic materials with zircon content.

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Influence of organobentonite structure on toluene adsorption from water solution

Cited by 13 publications

References 70 publications

Application of Organo-Magadiites for the Removal of Eosin Dye from Aqueous Solutions: Thermal Treatment and Regeneration

Application of Organo-Magadiites for the Removal of Eosin Dye from Aqueous Solutions: Thermal Treatment and Regeneration

Characterization of organo-kenyaites: thermal stability and their effects on eosin removal characteristics

High-temperature transformations of Zr-pillared bentonite

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