Extraction of metals from aqueous solution with polyurethane foam

Abstract

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(I1) is not extracted to any significant extent. Considerable amounts of hydrochloric acid are needed to reduce the uptake of iron(II1) 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(I1) from thiourea (3% w / 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(I1) and zinc from appropriate hydrochloric acid solutions, especially a t about 3 M hydrochloric acid, but there is little or no sorption of cobalt(II), copper(II), nickel(I1) and lead(I1) up to 10 M hydrochloric acid.The chelating extractant, 1-(2-pyridylaz0)-2-naphthol (PAN), is readily supported on unplasticised polyurethane foam and, when plasticised with a-dinonyl phthalate, the foam-supported material will extract zinc, mercury(I1) and copper(I1) from aqueous solution a t p H 8-9, and less effectively a t lower pH.

Polyurethane foams in chemical analysis: sorption of various substances and its analytical applications

“…The solvents play a dual role in this case: they should efficiently dissolve the reagents and should also act as plasticisers for the polymeric sorbent. Tributyl phosphate 57,192,213,215 and a-dinonyl phthalate 57,209,225 are used most often as plasticisers. Immobilisation of various chelating reagents on PUF has been described, for example, dimethylglyoxime, 204 ± 207 1-(2-pyridylazo)-2-naphthol, 14, 57, 208 ± 210 dithizone, 211 ± 219 ammonium pyrrolidinedithiocarbamate, 220,221,223 hexamethyleneammonium hexamethylenedithiocarbamate, 224 and sodium, 222 diethylammonium 225 and potassium 228 diethyldithiocarbamates.…”

Atomic Absorption Determination of Cobalt after Preconcentration by 1-(2-Pyridylazo)-2-naphthol Immobilized on Surfactant-Coated Alumina

“…The stability of PAN, its low solubility in water, and its ability to react with a large number of metals all suggest that it may have a promising role in preconcentration of trace metals if it is immobilized on an appropriate support. Polyurethane foam (18,19) and Amberlite XAD-4 (20) coated with PAN have already been reported as being good sorbents for trace metals. In this work, PAN is immobilized on SDS-coated alumina.…”

Functionalized polymer foams as metal ion chelating agents with rapid complexation kinetics

“…While convenient to preused in the batch extraction of metal ions. 14, 15 Solpare and utilize, gel beads can limit diffusion of vent extractants 16 and liquid ion exchangers 17 are substrates to the ligands, especially at the higher physically sorbed into the foams and act as the crosslink levels required to resist pressure drops metal ion chelants. in continuous operations.…”