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Study of copper complexes absorbed on a silica gel surface chemically modified with 5-amino-1,3,4-thiadiazole-2-thiol

Dias, N. L.
Fonte: Academic Press Inc. Publicador: Academic Press Inc.
Tipo: Artigo de Revista Científica Formato: 131-137
ENG
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The isotherms of adsorption of CuX2 (XCl-, Br-, ClO4-) by silica gel chemically modified with 5-amino-1,3,4-thiadiazole-2-thiol were studied in acetone and ethanol solutions, at 25 degrees C. The following equilibria constants (in L mol(-1)) were determined: (a) CuCl2, 3.2 x 10(3) (ac), 2.5 x 10(3) (eth); (b) CuBr2, 2.9 x 10(3) (ac), 2.3 x 10(3) (eth); (c) Cu(ClO4)(2), 1.8 x 10(3) (ac), 1.2 x 10(3) (eth); ac, acetone; eth, ethanol. The electron spin resonance spectra of the surface complexes indicated a tetragonal-distorted structure in the case of lower degrees of metal loading on the chemically modified surface. The d-d electronic transition spectra showed that for the ClO4- complex, the peak of absorption did not change for any degree of metal loading and for Cl- and Br- complexes, the peak maxima shifted to higher energy with lower metal loadings. (C) 1998 Academic Press.

Determination of metal ions in natural waters by flame-AAS after preconcentration on a 5-amino-1,3,4-thiadiazole-2-thiol modified silica gel.

Padilha, P. D.; Gomes, LAD; Padilha, CCF; Moreira, J. C.; Dias, N. L.
Fonte: Marcel Dekker Inc Publicador: Marcel Dekker Inc
Tipo: Artigo de Revista Científica Formato: 1807-1820
ENG
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3359.2488%
5-amino-1,3,4-thiadiazole-2-thiol groups attached on a silica gel surface have been used for adsorption of Cd(II), Co(II), Cu(II), Fe(III), Ni(II), Pb(II) and Zn(II) from aqueous solutions. The adsorption capacities for each metal ion were (in mmol.g(-1)): Cd(II)= 0.35, Co(II)= 0.10, Cu(II)= 0.15, Fe(III)= 0.20, Hg(Il)= 0.46, Ni(II)= 0.16, Pb(II)= 0.13 and Zn(II)= 0.15. The modified silica gel was applied in the preconcentration and quantification of trace level metal ions present in water samples (river, and bog water).

Determination of metal ions in fuel ethanol after preconcentration on 5-amino-1,3,4-thiadiazole-2-thiol modified silica gel

Gomes, Luis A. de Melo; Padilha, Pedro de Magalhães; Moreira, José Celso; Dias Filho, Newton L.; Gushikem, Yoshitaka
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 494-498
ENG
Relevância na Pesquisa
3656.429%
This work describes the synthesis and characterization of 5-amino-1,3,4-thiadiazole-2-thiol modified silica gel (SiATT), and the results of a study of the adsorption and preconcentration (in batch, and in flow using a column technique) of Cd(II), Co(II), Cu(II), Fe(III), Ni(II), Pb(II) and Zn(II) in ethanol medium. The adsorption capacities for each metal ion were (in mmol g -1): Cd(II) = 0.11, Co(II) = 0.10, Cu(II) = 0.20, Fe(III) = 0.20, Ni(II) = 0.16, Pb(II) = 0.08 and Zn(II) = 0.12. The results obtained in the flow experiments, showed a recovery of ca. 100% of the metal ions adsorbed in a column packed with 2 g of SiATT, using 5 mL of 2.0 mol L -1 HCl solution as eluent. The sorption-desorption of the metal ions made possible the development of a preconcentration method and quantification by Flame AAS of metal ions at trace level in fuel ethanol.

Determination of Metal Ions in Fuel Ethanol after Preconcentration on 5-Amino-1,3,4-Thiadiazole-2-Thiol Modified Silica Gel

Gomes,Luis A. de Melo; Padilha,Pedro de Magalhães; Moreira,José Celso; Dias Filho,Newton L.; Gushikem,Yoshitaka
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/1998 EN
Relevância na Pesquisa
3656.429%
This work describes the synthesis and characterization of 5-amino-1,3,4-thiadiazole-2-thiol modified silica gel (SiATT), and the results of a study of the adsorption and preconcentration (in batch, and in flow using a column technique) of Cd(II), Co(II), Cu(II), Fe(III), Ni(II), Pb(II) and Zn(II) in ethanol medium. The adsorption capacities for each metal ion were (in mmol g-1): Cd(II) = 0.11, Co(II) = 0.10, Cu(II) = 0.20, Fe(III) = 0.20, Ni(II) = 0.16, Pb(II) = 0.08 and Zn(II) = 0.12. The results obtained in the flow experiments, showed a recovery of ca. 100% of the metal ions adsorbed in a column packed with 2 g of SiATT, using 5 mL of 2.0 mol L-1 HCl solution as eluent. The sorption-desorption of the metal ions made possible the development of a preconcentration method and quantification by Flame AAS of metal ions at trace level in fuel ethanol.