Dias, N. L.2014-05-202014-05-201998-10-01Journal of Colloid and Interface Science. San Diego: Academic Press Inc., v. 206, n. 1, p. 131-137, 1998.0021-9797http://hdl.handle.net/11449/10001The 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.131-137engsilica gel5-amino-1,3,4-thiadiazole-2-thiolsilica gel modified with 5-amino-1,3,4-thiadiazole-2-thiolcopper complexelectron spin resonance of copper complexesArtigo10.1006/jcis.1998.5660WOS:000076375400016Acesso restrito