Separation and preconcentration of ionic solutes by transport extraction based on solvent sublation

The experimental capabilities of transport extraction were investigated by the help of a complex of molecular iodine with ionic surfactants. The extraction efficiency up to 95 % was obtained with a 400-fold preconcentration of iodide into benzene, using N-cetylpyridinium chloride. Moreover, anew method of sorbent-supported transport extraction by means of a resilient open-cell polyurethane foam has also been elaborated. The method was demonstrated in the separation of radioiodine from 4 dm3 of deionized, drinking or surface waters with N2 carrier gas in about 60-90 min. The intercomparison showed that the nonequilibrium transport extraction gives some distinctive advantages over equilibrium solvent extraction. The kinetics of the transport extraction has also been established, from which the mass-transfer rate constant of the process can be evaluated, and the separation efficiency can be predicted in dependence on time. (authors)