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

Abstract

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.

RETRACTED: Immobilization of 5-amino-1,3,4-thiadiazole-thiol onto kanemite for thorium(IV) removal: Thermodynamics and equilibrium study

“…In fact, this cation acts as acidic Lewis centers that interact with the basic Lewis center attached to the pendant molecules covalently bonded to the silicate surface [46]. Such processes occurring at the solid/liquid interface give the isotherms that demonstrate the saturation of the solid samples with a definite number of moles of metallic cation, as clearly shown in Fig.…”

Structural Model and De-Intercalation Kinetics of Kaolinite-Methanol-Sodium Stearate Intercalation Compound

“…As is known for Ka, the absorption bands at 3686 and 3655 cm −1 are ascribed to the stretches of inner-surface hydroxyls, whose intensities and positions are usually affected by intercalation and grafting of guest molecules, whereas the band at 3620 cm −1 belongs to the stretch of inner hydroxyls and it is generally not affected by guest molecules. 6,24,25 Additionally, the vibrational bands at 938 and 913 cm −1 are associated with the bend of inner-surface O−H and Al−OH groups of Ka, respectively. 26,27 The grafting of methanol molecules lead to a shift of Al−OH bending band at 913 to 906 cm −1 with a significant intensity loss (Figure 3b), indicating the formation of methoxy groups between methanol and inner-surface Al−OH groups of Ka via an alcohol condensation reaction.…”

Amazon kaolinite functionalized with diethylenetriamine moieties for U(VI) removal: Thermodynamic of cation-basic interactions

“…Certain factors influence the amount of metal ions being adsorbed by mineral substrates; pH, nature of the adsorbent, adsorbent dose, initial metal ion concentration, ionic strength, and presence of competing ions. A potential important adsorbent of uranyl is layered silicates, such as kaolinite [9,10]. Kaolinite is an important phyllosilicate with flake type morphology in industrial applications due to its relevant physical and chemical properties [11].…”

“…There are large reserves of kaolinite in north Brazil, Amazon region. The specific physical-chemical properties and large distribution of kaolinite make it to be studied and used extensively as adsorbent [9].…”

“…Designed applications to improve environmental quality through radionuclide removal have recently been emerged. Moreover, the versatility of the kaolinite clay support to be chemically modified induces its application to produce new materials available to remove contaminates from water and soils [9,16].…”