The conditions for the sorption of certain metal cations by polyether-type polyurethane foam have been studied. Cobalt(II), iron(III), zinc and cadmium sorb from aqueous thiocyanate solution, whereas nickel(II) is not extracted to any significant extent. Considerable amounts of hydrochloric acid are needed to reduce the uptake of iron(III) by the foam. The metal thiocyanato complexes can be desorbed with hot 0.1 M nitric acid.

Polyurethane foam can support various solvent extractants, and the sorption and separation elution of bismuth and nickel(II) from thiourea (3%m/V)-sodium perchlorate (1%m/V)-perchloric acid (0.1 M) by tributyl phosphate supported on the foam is described. Amberlite LA-2 supported on the foam sorbs iron(III), tin(IV), cadmium, mercury(II) and zinc from appropriate hydrochloric acid solutions, especially at about 3 M hydrochloric acid, but there is little or no sorption of cobalt(II), copper(II), nickel(II) and lead(II) up to 10 M hydrochloric acid.

The chelating extractant, 1-(2-pyridylazo)-2-naphthol (PAN), is readily supported on unplasticised polyurethane foam and, when plasticised with α-dinonyl phthalate, the foam-supported material will extract zinc, mercury(II) and copper(II) from aqueous solution at pH 8–9, and less effectively at lower pH.