Adsorption of uranyl(II) into modified lamellar Na-Kanemite

Guerra, Denis L.; Pinto, Alane A.; Airoldi, Cláudio; Viana, Rúbia Ribeiro

doi:10.1016/j.inoche.2008.01.027

Cited by 12 publications

(17 citation statements)

References 20 publications

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“…20 Both cations presented similar isotherms with kaolinite and its intercalated and delaminated forms, as exemplified for copper in Figure 7 and lead in Figure 8. As observed, for the matrix containing urea, the adsorption amounts are higher at the saturation isotherm plateau.…”

Section: Cation Adsorptionmentioning

confidence: 58%

“…Thus, the number of moles of cation adsorbed (N f ) increased with its concentration in the supernatant (C s ) as a function of pH during 12 h, until a plateau was reached, indicating total saturation of the acidic centers in the layered structure. [19][20][21] The most commonly used isotherm is that proposed by Langmuir, which was originally derived for gas adsorption on planar surfaces such as glass, mica and platinum. However, this procedure has also been applied to cation adsorption on porous surfaces in the classical Vol.…”

Section: Adsorptionmentioning

confidence: 99%

“…For this adsorption model, the amount of the adsorbate in the equilibrium solution upon reaching the plateau of the isotherm enabled determination of the K L and b parameters, which reflect the activity of the surface for the adsorbing species. The constant b establishes the upper limit for adsorption and represents the maximum value, determined by the number of reactive surface sites in kaolinite structure, [19][20][21] where K RP and K T are constants related to adsorption capacity and n is an affinity constant of the adsorbent. Although equation 4 was previously employed empirically, it can be derived with the assumption of a continuous variation in thermal effect during adsorption.…”

Section: Adsorptionmentioning

confidence: 99%

“…20 Thus, adsorption at a surface or interface is mainly a result of binding forces between the individual atoms, molecules or ions of the adsorbate to the surface, all of these forces having some electrostatic effects to promote interaction. 21 Divalent cations (M 2+ ) can be adsorbed on the available surface sites, denoted by ≡SOH, where S represents silicon or aluminum atoms in the inorganic structure, these atoms being main elements in the clay composition, as listed in Table 2.…”

Section: Cation Adsorptionmentioning

confidence: 99%

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The performance of urea-intercalated and delaminated kaolinites-adsorption kinetics involving copper and lead

Guerra¹,

Airoldi²

2009

J. Braz. Chem. Soc.

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Amostras brasileiras de caulinita foram usadas no estudo dos processos de intercalação com uréia (K UR ) e de deslaminação (K UR/DL ). A amostra intercalada foi deslaminada por tratamento com ultra-som em solução ácida. A distância basal inicial de 0,72 nm passa a 1,08 nm com aumento na área superficial de 20,3 para 90,5 m 2 g -1 para K NAT e K UR/DL . Amostras de argila intercalada e deslaminada adsorveram cátions cobre e chumbo na interface sólido/líquido. Os modelos de isotermas de adsorção de Langmuir, Redlich-Peterson e Toth foram utilizados em processo de regressão linear e não linear para a obtenção de valores de b e K L para todas as amostras de caulinita. A capacidade de adsorção mais alta, de 12,8 mmol g -1 , foi obtida com a caulinita deslaminada. Os parâmetros cinéticos analisados pelos modelos de Lagergren e Elovich forneceram um bom ajuste para uma reação de pseudo-segunda ordem com valores de k 2 variando de 5,0 a 11,0 e de 4,9 a 13,0 mmol -1 min -1 para cátions cobre e chumbo, respectivamente.Brazilian kaolinite clay was used to study urea intercalation (K UR ) and delamination (K UR/DL ) processes. The intercalated sample was delaminated by ultrasonic treatment in acidic solution. The basal distance changed from 0.72 to 1.08 nm with increasing surface area from 20.3 to 90.5 m 2 g -1 for K UR and K UR/DL . Suspended pristine, intercalated and delaminated clays at pH 5.0 adsorbed copper and lead cations at the solid/liquid interface. The Langmuir, Redlich-Peterson and Toth adsorption isotherm models were employed in linear and nonlinear regression processes, to give b and K L values for all kaolinites. The highest adsorption capacity of 12.8 mmol g -1 was obtained with delaminated kaolinite. The kinetic parameters analyzed by the Lagergren and Elovich models gave a good fit for a pseudo-second order reaction with k 2 in the 5.0 to 11.0 and the 4.9 to 13.0 mmol -1 min -1 ranges for copper and lead cations, respectively.

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Section: Cation Adsorptionmentioning

confidence: 58%

Section: Adsorptionmentioning

confidence: 99%

Section: Adsorptionmentioning

confidence: 99%

Section: Cation Adsorptionmentioning

confidence: 99%

See 2 more Smart Citations

The performance of urea-intercalated and delaminated kaolinites-adsorption kinetics involving copper and lead

Guerra¹,

Airoldi²

2009

J. Braz. Chem. Soc.

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“…The original and modified matrices adsorption capacities for the arsenic halide by modified smectite samples depend on the nature of the complex formed on the surface and also on the affinity of arsenic (V) cation for the particular attached ligand [14,15] and on the number of reactive groups anchored in the structure inorganic matrix. The maximum adsorption capacities obtained experimentally, N f max , for arsenic (V) halide on S and S MPY are listed in Table I.…”

Section: Adsorption Studymentioning

confidence: 99%

Performance of natural and modified smectite: kinetic and thermodynamics involving arsenic (V) adsorption

2010

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A natural smectite sample has been modified by organofunctionalization process using synthetic route involved the reaction of 2-mercaptopyrimidine with 3-chloropropyltriethoxysilane. The resulting material (S MPY ) was characterized by SEM, FTIR, textural analysis and 29 Si MAS-NMR. The ability of this material to removed As (V) from aqueous solution was followed by series of adsorption isotherms adjusted to the Langmuir equation at room temperature and pH 2.0. The kinetic parameters analyzed by Lagergren and Elovich models gave a good fit for a pseudo-second order reaction with k 2 in the 4.9 to 14.0 mmol -1 min -1 range for S MPY . The adsorption process was exothermic (D int H = -4.09 to -5.79 kJ.mol -1 ) accompanied by increase in entropy (D int S = 41.29 to 61.80 JK -1 .mol -1 ) and Gibbs energy (D int G = -22.34 to -24.19 kJmol -1 ). The energetic effect caused by arsenic cation adsorption was determined through calorimetric titration at the solid-liquid interface and gave a net thermal effect that enabled the calculation of the exothermic values and the equilibrium constant. Keywords: adsorption, smectite, kinetic, thermodynamic, arsenic. Resumo Uma amostra de esmectita natural foi modificada por processo de organofuncionalização usando rota sintética, envolvendo a reação de 2-mercaptopirimidina com 3-cloropropiltrietoxisilano. O material resultante (S MPY)

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