Resumen

FERREIRA, Elizabeth de M. M.; MORELLI, Tadeu; MOREIRA, Isabel M. N. S.  y  CARVALHO, Marcelo S. de. Studies on indium sorption from iodide medium by polyurethane foam. J. Braz. Chem. Soc. [online]. 2004, vol.15, n.4, pp. 563-569. ISSN 0103-5053.  http://dx.doi.org/10.1590/S0103-50532004000400019.

The sorption behavior of indium iodide onto polyether-based polyurethane (PUF) foam was investigated. The system shows rapid kinetics and maximum sorption from a meaningful range of either acidic or basic media and achieves distribution ratios above 10⁴ L kg^-1 ([KI] > 0.6 mol kg^-1). Sorption equilibrium analysis indicates tetraiodo-indate (MInI₄) as the main species sorbed on the foam matrix. A Langmuir isotherm was successfully fitted and values of (1.55±0.02) x 10^-1 mol kg^-1 and (7.0±1.3) x 10⁴ L g^-1 were obtained for the saturation capacity K_s and adsorption coefficient b, respectively. The temperature effect was evaluated and the thermodynamic parameters calculated. The values of the equilibrium constant, K_c, decreased with increasing temperature. The negative values of DG, DH and DS indicate a spontaneous and exothermic chemisorption process favored at low temperatures.

Palabras llave : polyurethane foam; indium; solid-phase extraction.