Artículos de revistas
Adsorption Of Uranyl(ii) Into Modified Lamellar Na-kanemite
Registro en:
Inorganic Chemistry Communications. , v. 11, n. 5, p. 539 - 544, 2008.
13877003
10.1016/j.inoche.2008.01.027
2-s2.0-43049153370
Autor
Guerra D.L.
Pinto A.A.
Airoldi C.
Viana R.R.
Institución
Resumen
The Na-Kanemite sample was used for organofunctionalization process with N-propyldiethylenetrimethoxysilane and 3-aminopropyltriethoxysilane, after expanding the interlayer distance with polar organic solvents such as dimethyl sulfoxide (DMSO). The new organofunctionalized matrix was characterized by carbon nuclear magnetic resonance in the solid state SEM and chemical analysis. The resulted material was submitted to the process of adsorption with uranyl(II) at pH 2.0 and 298 ± 1 K. The Langmuir adsorption isotherm model has been to fit the experimental data with regression non-linear; the net thermal effects obtained from calorimetric titration measurements were adjusted to a modified Langmuir equation. The adsorption process was exothermic (ΔH = -7.14 to -5.98 kJ mol-1) accompanied by an increase in entropy (ΔS = 52.28-62.12 J K-1 mol-1) and Gibbs energy (ΔG = -22.62 to -24.44 kJ mol-1). The favorable values corroborate with the uranyl(II)/basic reactive centres interaction at the solid/liquid interface in the spontaneous process for the new nanomaterials. © 2008. 11 5 539 544 Atia, A.A., (2005) Hydrometallurgy, 80, p. 13 Egawa, H., Nonaka, T., Nakayama, M., (1988) J. Macromol. Sci. Chem., A 25 (10-11), p. 1407 Pekel, N., Şehiner, N., Akkaş, P., Güven, O., (2000) Polym. Bull., 44, p. 593 Zhang, A., Asakura, T., Uchiyama, G., (2003) React. Funct. Polym., 57, p. 67 Štamberg, K., Venkatesan, K.A., Rao, P.R.V., (2003) Colloid Surf., 221, p. 149 Brynda, M., Wesolowski, T.A., Wojcichowski, K., (2004) J. Phys. Chem. A, 108 (23), p. 5091 Hennig, C., Reich, T., Dähn, R., Scheidegger, A.M., (2002) Radiochim. Acta, 90, p. 653 Froideval, A., Del Nero, M., Barillon, R., Hommet, J., Mignot, G., (2003) J. Colloid Interface Sci., 266, p. 221 Inagaki, S., Koiwai, A., Suzuki, N., Fukushima, Y., Kuroda, K., (1996) Bull. Chem. Soc. Jpn., 69, p. 1449 Guerra, D.L., Lemos, V.P., Airoldi, C., Angélica, R.S., (2006) Polyhedron, 25, p. 1880 Guerra, D.L., Airoldi, C., (2008) Inorg. Chem. Commun., 11, p. 20 Ansari, S.A., Mohapatra, P.K., Manchanda, V.K., (2007) Talanta, 73, p. 878 Hidaka, H., Horie, K., Gauthier-Lafaye, F., (2007) Earth Planet. Sci. Lett., 264, p. 167 The Na-Kanemite was prepared by the calcination of 20.0 g of sodium silicate at 700 C for 6 h to obtain δ-Na2 Si2 O5 in 500.0 cm3 of ethanol and stirred by 3 h at 77 K in nitrogen atmosphere. Centrifugation of the dispersion gave us a Na-Kanemite paste. The resulted material was dried in 318 ± 1 K and named Na-K. The two portions of about 10 g of Na-Kanemite were suspended in 25.0 cm3 of DMSO under a nitrogen purge at 298 ± 1 K for 1 h. In each case, 3.0 cm3 of silylating agents was added under flowing nitrogen to the suspension and stirred for 1 h followed by another 72 h at 363 ± 1 K. The solid was filtered, washed with DMSO and again with acetone in a Soxhlet system to remove the inserting solvent from inside the layers, then dried in vacuum to yield the immobilized compounds denoted Na-KNPTM and Na-KAPTThe nuclear magnetic resonance spectrum was recorded with a Bruker AC300/P solid state high-resolution spectrometer, by using cross-polarization and magic angle spinning (CP-MAS). The frequency was 75.5 MHz, with a rotational frequency of 26 MHz and an acquisition time of 0.8 s. The samples for scanning electron microscopy (SEM) images were recorded on a model LEO-ZEISS, 430 Vp at LNLS/Brazil, in the conditions of analysis using secondary images obtained at 20 kV, with a working distance of 11 mm. The surface and porosity analyses were carried out with a volumetric adsorption analyser, AZAP 2010, from Micrometrics, at 77 K. The samples were pre-treated at 373 K for 24 h. After this, the samples were submitted to 298 ± 1 K under vacuum, reaching the residual pressure of 10-4 Pa. For area and pore calculations, the DBET and BJH methods were evaluatedKaradag, D., Koc, Y., Turan, M., Ozturk, M., (2007) J. Hazard. Mater., 144, pp. 432-437 Prado, A.G.S., Airoldi, C., (2001) C. Anal. Chim. Acta, 432, p. 201 Machado, R.S.A., Fonseca, M.G., Arakaki, L.N.H., Oliveira, S.F., (2004) Talanta, 63, p. 317 Machado, M.O., Lazarin, A.M., Airoldi, C., (2006) J. Chem. Thermodyn., 38, p. 130 Ruiz, V.S.O., Airoldi, C., (2004) Thermochim. Acta, 420, p. 73 Monteiro, O.A.C., Airoldi, C., (2005) J. Colloid Interface Sci., 282, p. 32 Lazarin, A.M., Airoldi, C., (2006) J. Mater. Chem., 18, p. 2226