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Abstract: The original sepiolite clay mineral has been collected from Amazon region, Brazil. The compound 2-aminomethylpyridine (AMP) was anchored onto Amazon sepiolite surface by heterogeneous route. The natural (SPT) and modified (SPTAMP) sepiolite samples were characterized by elemental analysis, SEM, N2 adsorption, and nuclear magnetic nuclei of 29Si and 13C. The well-defined peaks obtained in the 13C NMR spectrum in the 0–160ppm region confirmed the attachment of organic functional groups as pendant chains bonded into the porous clay. The ability of these materials to remove As(V) from aqueous solution was followed by a series of adsorption isotherms at room temperature and pH 4.0. The maximum number of moles adsorbed was determined to be 7.26×10−2 and 11.70×10−2 mmolg−1 for SPT and SPTAMP, respectively. In order to evaluate the clay samples as adsorbents in dynamic system, a glass column was fulfilled with clay samples (1.0g) and it was fed with 2.0×10−2 mmoldm−3 As(V) at pH 4.0. The energetic effects caused by metal cations adsorption were determined through calorimetric titrations. Thermodynamics indicated the existence of favorable conditions for such As(V)–nitrogen interactions. [Copyright &y& Elsevier]

Abstract: The compound 5-amino-1,3,4-thiadiazole-thiol (ATT) was anchored onto an Amazon kanemite surface (K) by homogeneous and heterogeneous routes. Both kanemite modification methodologies resulted in similar products, named K CTT and K ATT, respectively. The modified and natural kanemite samples were characterized by textural analysis, FT-Raman, and nuclear magnetic nuclei of 29Si and 13C. Elemental analysis proved that the matrix K ATT presented a higher ATT immobilization than K CTT, with values 1.42 and 1.38mmolg−1, respectively. NMR and FT-Raman confirmed the immobilization of ATT on both surfaces. 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 4.0. The maximum number of moles adsorbed was determined to be 7.48×10−3, 9.82×10−3, and 12.94×10−3 mmolg−1 for K, K CTT, and K ATT, respectively. The energetic effects (Δint H°, Δint G°, and Δint S°) caused by metal cation adsorption were determined through calorimetric titrations. [Copyright &y& Elsevier]

Abstract: An analogue of heulandite was synthesized by using inorganic salts as a source for silicon and aluminum in the hydrothermal synthesis of the material. The resulting solid was modified by organofunctionalization with 1,4-bis(3-aminopropyl)piperazine and subsequent reaction with methylacrylate in a heterogeneous route. The original (HEU) and modified silicate (HEUAPPMA) samples were characterized by textural analysis, SEM, and nuclear magnetic nuclei of 29Si and 13C. The chemically modified silicate sample showed modification of its physical–chemical properties including specific area 459.0–978.8m2 g−1. The ability of this material to remove nickel(II), cobalt(II), and copper(II) from aqueous solutions was followed by a series of adsorption isotherms adjusted to a Sips equation. The quick adsorption process reached the equilibrium before 10, 15, and 20min for Cu(II), Ni(II), and Co(II), respectively, with maximum adsorptions at pH 4.0. Based on the capacity of adsorption of HEUAPPMA to interact with metal ions, the following results were obtained 12.9, 9.8, and 7.5mmolg−1 for Cu(II), Ni(II), and Co(II), respectively, reflecting a maximum adsorption order of Cu(II)>Ni(II)>Co(II). The energetic effects caused by metal cation adsorption were determined through calorimetric titrations. [Copyright &y& Elsevier]