Some thermodynamic data about amino chrysotile derivatives with nickel and cobalt cation interactions in aqueous solution

Fonseca, Maria G. da; Simoni, José A.; Airoldi, Cláudio

doi:10.1016/s0040-6031(00)00750-4

Cited by 23 publications

(22 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A possible explanation for this enhancement in adsorption with temperature is the activation of the remaining basic centers of original structure on the clay, possibly arising from displacement of water initially hydrogen bonded to the clay and the modified surfaces. 34 These N f max values reflect the good affinity of the sulfur donor atom attached to the inorganic backbone for bonding mercury. A favorable sulfur/ mercury interaction was previously observed for this same silylating agent when immobilized on phyllosilicate.…”

Section: Adsorption Studymentioning

confidence: 97%

“…33,34 The maximum cation adsorption capacity, N f max , for natural and organofunctionalized smectites is listed in Table 3, with the highest values for the chemically modified surfaces, showing also an increase with temperature. A possible explanation for this enhancement in adsorption with temperature is the activation of the remaining basic centers of original structure on the clay, possibly arising from displacement of water initially hydrogen bonded to the clay and the modified surfaces.…”

Section: Adsorption Studymentioning

confidence: 99%

“…A favorable sulfur/ mercury interaction was previously observed for this same silylating agent when immobilized on phyllosilicate. 34 …”

Section: Adsorption Studymentioning

confidence: 99%

“…The Gibbs free energy associated with divalent mercury/natural or organofunctionalized smectite adsorptions can be determined by the Langmuir constant K L . [27][28][29][30][31][32][33][34] The enthalpy (∆ r h) is related to the thermal effect per mass for each matrix, ∆ int h, which corresponds to the enthalpy of monolayer formation. ∆ int h and K L values can be determined from coefficients after isotherm linearization.…”

Section: Thermodynamic Studymentioning

confidence: 99%

See 3 more Smart Citations

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

Guerra¹,

Santos²,

Airoldi³

2009

J. Braz. Chem. Soc.

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Adsorption Studymentioning

confidence: 97%

Section: Adsorption Studymentioning

confidence: 99%

“…A favorable sulfur/ mercury interaction was previously observed for this same silylating agent when immobilized on phyllosilicate. 34 …”

Section: Adsorption Studymentioning

confidence: 99%

Section: Thermodynamic Studymentioning

confidence: 99%

See 2 more Smart Citations

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

Guerra¹,

Santos²,

Airoldi³

2009

J. Braz. Chem. Soc.

Self Cite

View full text Add to dashboard Cite

show abstract

“…In fact, this cation acts as on acidic Lewis center that interacts with the basic Lewis centers attached to the pendant molecules covalently bonded to the modified clay surfaces. [19][20][21][22][23][24][25][26][27] Processes occurring at the solid/liquid interface give the isotherms that demonstrate the saturation of the natural and modified clay samples with a definite number of moles of tetravalent metallic cations, as clearly shown in Figures 5a and 5b with the highest pronounced adsorption for S HOM and S HET , respectively. Based on the ability of the pendant groups attached to the inorganic backbone in coordinating this metallic cation, the quantity can be related to N f max , which presents the values for the metal/clay system of 9.57, 9.89, 8.29 and 8.86 × 10 -1 mmol g -1 for S HOM , S HET , K HOM and K HET , respectively (see Table 3).…”

Section: Adsorption and Thermodynamic Studiesmentioning

confidence: 99%

Adsorption of thorium(IV) on chemically modified Amazon clays

Guerra¹,

Viana²,

Airoldi³

2009

J. Braz. Chem. Soc.

Self Cite

View full text Add to dashboard Cite

Amostras de caulinita e esmectita oriundas da região Amazônica, Brasil, foram modificadas com 2-mercaptobenzimidazol (MBI) usando rotas homogênea e heterogênea. As amostras de argilas modificadas (K HOM, S HOM , K HET e S HET ) foram caracterizadas por análise textural, MEV e espectroscopia 13 C NMR. As argilas modificadas quimicamente apresentaram modificações em suas propriedades físico-químicas incluindo: área específica 48,0 (S) para 869,8 m 2 g -1 (S HET ). A habilidade destes materiais para remover tório(IV) em soluções aquosas foi investigada por um série de isotermas de adsorção ajustadas pela equação de Sips em temperatura ambiente e pH 2,0. O número máximo de mols adsorvidos foi determinado em 8,29,8,86,9,57 e 9,89 10 -1 mmol g -1 para K HOM , K HET , S HOM e S HET , respectivamente. Os efeitos energéticos causados pela adsorção do cation tório(IV) foram determinados através de metodologia calorimétrica.Kaolinite and smectite clay samples from the Amazon region, Brazil, were modified with 2-mercaptobenzimidazole (MBI) using homogeneous and heterogeneous routes. The modified clay samples (K HOM , S HOM , K HET and S HET ) were characterized by textural analysis, SEM and 13 C NMR spectroscopy. The chemically modified clay samples showed modifications of their physicalchemical properties including: specific area 48.0 (S) to 869.8 m 2 g -1 (S HET ). The ability of these materials to remove thorium(IV) from aqueous solution was followed by a series of adsorption isotherms adjusted to a Sips equation at room temperature, and pH 2.0. The maximum number of moles adsorbed was determined to be 8. 29, 8.86, 9.57 and 9.89 10 -1 mmol g -1 for K HOM , K HET , S HOM and S HET , respectively. The energetic effects (∆ int H, ∆ int G and ∆ int S) caused by thorium(IV) cation adsorption were determined through calorimetry.

show abstract

Flow microcalorimetry: Experimental development and application to adsorption of heavy metal cations on silica

Lantenois

Prelot

Douillard

et al. 2007

Applied Surface Science

View full text Add to dashboard Cite

Some thermodynamic data about amino chrysotile derivatives with nickel and cobalt cation interactions in aqueous solution

Cited by 23 publications

References 21 publications

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

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

Adsorption of thorium(IV) on chemically modified Amazon clays

Flow microcalorimetry: Experimental development and application to adsorption of heavy metal cations on silica

Contact Info

Product

Resources

About