Extraction of Cobalt Ion from Textile Using a Complexing Macromolecular Surfactant in Supercritical Carbon Dioxide

Cobalt ion under the form of cobalt nitrate is removed from a textile lab coat using supercritical carbon dioxide extraction. The process involves a macromolecular additive of well-defined architecture, acting both as a surfactant and a complexing agent. The extraction efficiency of cobalt reaches 66% when using a poly­(1,1,2,2-tetrahydroperfluorodecylacrylate-<i>co</i>-vinylbenzylphosphonic diacid) gradient copolymer in the presence of water at 160 bar and 40 °C. The synergy of the two additives, namely the copolymer and water which are useless if used separately, is pointed out. The potential of the supercritical carbon dioxide process using complexing macromolecular surfactant lies in the ability to modulate the complexing unit as a function of the metal as well as the architecture of the surface-active agent for applications ranging for instance from nuclear decontamination to the recovery of strategic metals