PREPARATION OF MICROCAPSULES CONTAINING A METAL EXTRACTANT

The microencapsulation of metal extractants, 2-hydroxyoximes and EDTA, into polyhexamethylene phthalamide and polyhexamethylene sebacamide m icrocapsules prepared by an interfacial polycondensation was studied. The influence of the surfactant concentration and the stirring speed o n the size of the microcapsules was also examined. The lipophilic 2-hy droxyoximes were introduced as a form of copper complex into the organ ic core at the polycondensation step in O/W emulsion followed by the r emoval of copper by acid or impregnated after polycondensation with an organic solution of the extractant. The hydrophilic EDTA was introduc ed into the aqueous core at the polycondensation step in the W/O emuls ion. All microcapsules impregnated by the extractants showed remarkabl e extractability for copper. Incorporation of colloidal magnetite was shown to be effective for collecting microcapsules by the use of an ex ternal magnetic field.