MORPHOLOGY OF SOLVENT-IMPREGNATED RESINS BASED ON REACTIVE SUPPORTS

Hydrophobic metal-complexing extractants of the alkylphosphoric acid t ype (di-(2-ethylhexyl)dithiophosphoric acid, di-(2-ethylhexyl) monothi ophosphoric acid and di-(2-ethylhexyl)phosphoric acid) are used as lig ands for separation of metal ions from aqueous solutions. Upon immobil ization on polymer carriers containing vinylpyridine and alkylamine ba sic groups they are held by chemisorption and absorbed into the polyme r mass of the support. The capacity of the support for the organic lig and depends on the ability of its polymer mass to swell and also on th e strength of the interaction between the basic functional groups of t he polymer and the ligand. This is a newly observed phenomenon. Intera ction of the supported ligand with metal ions results in expulsion of the ligand from the polymer mass. In macroreticular polymeric supports the metal-saturated ligand fills the macropores and escapes from the support when the macropore volume of the support is smaller than the v olume of the organic ligand. Stripping of the metal from the ligand by washing with mineral acids causes the ligand to return from the macro pores into the polymer mass of the support.