Studies of the state of benzene molecules adsorbed on the surface of organoderivatives of kaolinite and silica

Tarasevich, Yu. I.; Polyakov, V. E.; Бондаренко, С. В.; Aksenenko, E. V.

doi:10.1016/j.colsurfa.2004.06.032

Cited by 8 publications

(10 citation statements)

References 13 publications

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“…Attention is drawn to the convex initial section of the isotherms not only for the hydromica but also for the hydrophobized samples of kaolinite and Silochrom. This is explained by the presence, on the surface of the last two sorbents, of residual hydrophilic centers, i.e., the secondary hydroxyl groups of the modifying layer of the Silochrom and the -NH 3 + …NH 2 -groups of the modifying layer on the surface of the kaolinite [6].…”

Section: Methodsmentioning

confidence: 99%

“…The procedures used for the modification of the sorbents were described in [6]. A reference samples we used an extremely hydrophobic sample of polytetrafluoroethylene (Teflon), the q and p values for which are given in the monograph [5], and a hydrophilic sample of Cherkassk hydromica in the potassium form, which makes it similar to muscovite in its characteristics.…”

Section: Methodsmentioning

confidence: 99%

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Surface energy of hydrophobic adsorbents

Tarasevich

2006

Theor Exp Chem

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The adsorption of water vapor and the heat of wetting of hydrophilic hydromica and hydrophobized samples of kaolinite and Silochrom were studied. The contact angles for the wetting of the investigated materials with water were obtained. The thermodynamic characteristics of the surface of the sorbents and the interfacial region at their boundary with water were calculated from the obtained data. It was shown that the boundary water layers close to the hydrophilic surface of the hydromica are more ordered while those close to the hydrophobic surfaces of the modified samples of kaolinite, Silochrom, and the reference sample (extremely hydrophobic Teflon) are less ordered than liquid water.Surface energy is an important characteristic of solids. In contrast to liquids, however, the direct experimental measurement of the surface free energy (thermodynamic surface tension) s of solids is quite complicated. In the case of solids with a low-energy surface such as polymers, for which the thermodynamic surface tension is approximately equal to the mechanical surface tension g, investigators usually determine the wetting angle q of the solid with the liquid experimentally and then use Young's equation and various empirical approximations to determine the s (g) value of the solid [1-3].For a more objective thermodynamic characterization of the surface apart from the value of s [the excess Helmholtz free energy (isochoric-isothermal potential)] it is also necessary to know the excess surface enthalpy H = U + pV (since pV is small, H~U, where U is the surface total energy of the solid) and the excess entropy S. To calculate these thermodynamic parameters it is necessary first to determine experimentally the surface pressure of the adsorbed film of wetting liquid on the surface of the solid p and its specific heat of wetting q [4].Determination of the p and q values for the hydrophobic surfaces of the polymeric materials involves great experimental difficulties. In most papers on the surface free energy of polymers, therefore, the investigators restricted themselves to determination only of s without correction for the surface pressure. In the mean time it was shown that even for systems characterized by a contact angle greater than 90°(e.g., for the Teflon-water system) the correction to the determined value of s can reach 10% [5].In the present work measurements and calculations required for the determination of q, p, and q were made for the investigated materials. This made it possible to determine the excess thermodynamic characteristics of the surface of the materials s S , H S , and S S and also the excess interfacial thermodynamic characteristics of the investigated sorbents in relation to liquid water s SL , H SL , and S SL . 960040-5760/06/4202-0096

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Surface energy of hydrophobic adsorbents

Tarasevich

2006

Theor Exp Chem

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“…For the adsorption of hydrocarbons by zeolites the coefficient f is actually equal to 0.3-0.4. However, for the supermobile adsorption of benzene molecules on an organic derivative of Silochrome [38] at x = 0.11 the calculated coefficient f = 0.66 is twice the value (f = 0.3-0.4) recommended in [33].…”

mentioning

confidence: 98%

“…The interaction of water, benzene, and hexane with the hydrophobic zeolite ZSM-83 is reflected in [39], and the interaction of benzene and hexane with the highly dealuminated zeolite Y-US-Ex and a laminar microporous sorbent based on 28 ] 3+ is reflected in the investigations in [40] and [41] respectively. The results in [37][38][39][40][41] are summarized in Table 1. For comparison it also contains data for the zeolite NaA-water system obtained in the Dubinin's laboratory (Moscow) [42] and the thermodynamic characteristics of the hexane (benzene)-Silicalite systems [36] obtained in the laboratory of G. Stach (Berlin).…”

mentioning

confidence: 99%

“…Concerning the thermodynamics of adsorption, in our earlier papers a set of data on the heats and entropies of adsorption of water, benzene, and hexane vapor both on nonporous and on microporous zeolites was obtained. This refers primarily to the adsorption of water and benzene on the hydrophilic Li form and hydrophobized samples of structurally imperfect kaolinite organically substituted within the limits of the cation-exchange capacity (RNH 3 ) and above the cation-exchange capacity (RNH 3 , RNH 2 ) [37], where R is an octadecyl radical, and also on the highly hydrophobic sample of Silochrome modified with polyalkylhydridesiloxane [38]. The interaction of water, benzene, and hexane with the hydrophobic zeolite ZSM-83 is reflected in [39], and the interaction of benzene and hexane with the highly dealuminated zeolite Y-US-Ex and a laminar microporous sorbent based on 28 ] 3+ is reflected in the investigations in [40] and [41] respectively.…”

mentioning

confidence: 99%

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Energetics of the interaction of water and other liquids with the surface of hydrophilic and hydrophobic sorbents according to data on the heats of wetting

Tarasevich

2008

Theor Exp Chem

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Papers on the energetics of the interaction of various substances with the surface of hydrophilic and hydrophobic sorbents using the data from heats of wetting are reviewed. The thermodynamics of wetting is examined, and the important role of the heats of wetting for the production of quantitative data on the surface energy of solids is demonstrated. The uniqueness of the information on the physicochemical characteristics of the sorbents and catalysts obtained from the immersion wetting isotherms is emphasized, and up-to-date information on the extent, structure, and characteristics of the boundary layers of water is analyzed. It is shown that the calorimetric data serve as an experimental base for obtaining data on the structural ordering-disordering of the boundary layers of water.

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Benzene–kaolinite interaction properties

Castro

Gargano

Martins

2011

Int J of Quantum Chemistry

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In this work, we present a theoretical study of interaction of benzene with kaolinite and an analysis of the vibrational spectra, electrostatic potential maps, and self consistent field (SCF) orbitals. B3LYP and MP2 benzene-kaolinite results indicate a preferential interaction of benzene on kaolinite octahedral surface. Population analysis indicates that the atoms modified their charges when the monoaromatic molecule and clay mineral are close to tetrahedral and octahedral surface of kaolinite, which suggests that the adsorbed molecule becomes slightly positive. Infrared vibrational data show the reduction in the band frequencies related to the kaolinite external hydroxyls, indicating a weak interaction of benzene with clay mineral. It also was verified, from the potential electrostatic maps, a change in electron density in both benzene and kaolinite. Electron localization function analysis was also carried out for this interaction.

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Studies of the state of benzene molecules adsorbed on the surface of organoderivatives of kaolinite and silica

Cited by 8 publications

References 13 publications

Surface energy of hydrophobic adsorbents

Surface energy of hydrophobic adsorbents

Energetics of the interaction of water and other liquids with the surface of hydrophilic and hydrophobic sorbents according to data on the heats of wetting

Benzene–kaolinite interaction properties

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