Journal of the Brazilian Chemical Society
On-line version ISSN 1678-4790
FERREIRA, Elizabeth de M. M.; MORELLI, Tadeu; MOREIRA, Isabel M. N. S. and 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 1678-4790. 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 Ks and adsorption coefficient b, respectively. The temperature effect was evaluated and the thermodynamic parameters calculated. The values of the equilibrium constant, Kc, decreased with increasing temperature. The negative values of DG, DH and DS indicate a spontaneous and exothermic chemisorption process favored at low temperatures.
Keywords : polyurethane foam; indium; solid-phase extraction.