The Intercalation of Some Heterocyclic Amines into α-Titanium Hydrogenphosphate—Structural and Calorimetric Data

Nunes, Liliane M.; Airoldi, Cláudio

doi:10.1006/jssc.2000.8879

Cited by 30 publications

(17 citation statements)

References 26 publications

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“…Thus, a plot of P X/ P Dh r vs. P X gives Dh int and K values from the angular and linear coefficients, respectively, after linearization of the equation, as shown in figure 4. and the number of moles of amine adsorbed after the calorimetric equilibrium is reached on the inorganic matrix n s , then, the enthalpy of interaction can be calculated by: DH = Dh int /n s , where 1/Dh int = b, that is angular coefficient obtained in figure 4, with n s being calculated from the batch process intercalation results [10,11,15,17,18]. It is worth mentioning that investigations involving calorimetric techniques to detect the thermal effects associated with intercalation processes are rare and this investigation deals with endeavors to increase the data available for such kinds of systems.…”

Section: Resultsmentioning

confidence: 99%

“…In such a case, a sequence of values was obtained from the calorimetric data to enable the calculation of the enthalpy of intercalation to form the monolayer per unit of mass of the host, Dh int , by using equation (4). The modified Langmuir equation was adapted to describe several types of systems [17] …”

Section: Resultsmentioning

confidence: 99%

“…Direct acquisition involving host-guest quantitative intercalation effects can be attained through the calorimetric technique, which provides, in one operation, the variation in enthalpy and the equilibrium constant determination at the solid/liquid interface, as reported for a limited number of systems [13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Calorimetric data on intercalation of some aromatic amines into barium phenylphosphonate at the solid/liquid interface

Lazarin

Airoldi

2005

The Journal of Chemical Thermodynamics

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Calorimetric data on intercalation of some aromatic amines into barium phenylphosphonate at the solid/liquid interface

Lazarin

Airoldi

2005

The Journal of Chemical Thermodynamics

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“…The same procedure for the isotherms of time and concentration was used to calculate the number of moles of the metallic cation adsorbed per gram (N f ), which is given by the difference between the initial (N i ) and the remaining number of moles of metal in the supernatant (N s ), divided by the mass (m) of the compound used, [17][18][19][20] as given in equation 1.…”

Section: Adsorptionmentioning

confidence: 99%

Mercury adsorption on natural and organofunctionalized smectites - thermodynamics of cation removal

Guerra¹,

Santos²,

Airoldi³

2009

J. Braz. Chem. Soc.

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Uma amostra natural de esmectita oriunda do estado do Piauí, Brasil, foi organofuncionalizada com 3-mercaptopropiltrimethoxissilano e 3-aminopropiltriethoxissilano. O espaçamento basal da argila natural é de 0,99 nm e área superficial 48 m 2 g -1. Houve um aumento no espaçamento basal para 1,84 e 2,01 nm e o aumento da área específica para 781 e 795 m 2 g -1 para as argilas quimicamente modificadas, respectivamente. A argila natural e a argila quimicamente modificada adsorveram cátions mercúrio em solução aquosa em pH 3,0 e 298 ± 1 K. Os modelos de isotermas de adsorção de Langmuir, Redlich-Peterson e Toth foram aplicados para ajuste dos dados experimentais com aproximação não linear. Para as interações cátion/centros básicos para cada esmectita na interface sólido/líquido foi utilizada metodologia calorimétrica e foram obtidas as constantes de equilíbrio e os efeitos térmicos exotérmicos. Considerando o número interativo de moles para cada cátion e as constantes de equilíbrio, a entalpia, ∆ int H o (−11,98 a −13,93 kJ mol ). As interações cátion/ centros básicos são de natureza espontânea como demonstram os valores de energia livre de Gibbs, dando o conjunto de dados favoráveis como expressam a entalpia exotérmica e a entropia positiva, mostrando que a esmectita natural e as quimicamente modificadas têm habilidade em complexar mercúrio. Logo, esses materiais são úteis na remoção de mercúrio em um ecossistema.A natural smectite clay sample from Piauí State, Brazil, was organofunctionalized with 3-mercaptopropyltrimethoxysilane and 3-aminopropyltriethoxysilane silyating agents. The basal spacing of 0.99 nm and surface area of 48 m 2 g -1 for natural clay increased to 1.84 and 2.01 nm, and 781 and 795 m 2 g -1 for modified clays, respectively. The natural and chemically immobilized clay samples adsorb mercury cations from aqueous solutions at pH 3.0 at 298 ± 1 K. The Langmuir, Redlich-Peterson and Toth adsorption isotherm models were applied to fit the experimental data with a nonlinear approach. From the cation/basic center interactions for each smectite at the solid-liquid interface, by using calorimetry methodology, the equilibrium constant and exothermic thermal effects were obtained. By considering the net interactive number of moles for each cation and the equilibrium constant, the enthalpy, ∆ int H o (−11.98 to −13.93 kJ mol ). The cation-basic center interactions are spontaneous in nature as demonstrated from favorable enthalpic and entropic results. Natural and anchored smectites have the ability to complex mercury, acting as useful materials for removal of this hazardous metal from an ecosystem.

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“…From the experimental point of view, a calorimetric technique was applied to the heterogeneous system and the interactive effect that occurred at the (solid + liquid) interface can be determined [21][22][23]. Examples of previous investigations have focussed upon some reactions involving alkylmonoamines [16], n-alkyldiamines [24], and some aromatic heterocyclic amines [25,26] with a-titanium hydrogenphosphate. Data on a series of n-alkylmonoamines with barium phosphate system are now presented.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic features associated with intercalation of some n-alkylmonoamines into barium phosphate

Machado

Lazarin

Airoldi

2006

The Journal of Chemical Thermodynamics

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The Intercalation of Some Heterocyclic Amines into α-Titanium Hydrogenphosphate—Structural and Calorimetric Data

Cited by 30 publications

References 26 publications

Calorimetric data on intercalation of some aromatic amines into barium phenylphosphonate at the solid/liquid interface

Calorimetric data on intercalation of some aromatic amines into barium phenylphosphonate at the solid/liquid interface

Mercury adsorption on natural and organofunctionalized smectites - thermodynamics of cation removal

Thermodynamic features associated with intercalation of some n-alkylmonoamines into barium phosphate

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