ADSORPTION BEHAVIOR OF METAL-IONS ON HYDROXIMATE RESINS

Some new chelating ion-exchange resins containing a hydroxamic acid mo iety attached to a divinylbenzene styrene (DVBS) copolymer, i.e. glyci ne hydroximate in DVBS (GH-DVBS), anthranilic acid hydroximate in DVBS (AAH-DVBS), malonic acid dihydroximate in DVBS (MAH-DVBS) and iminodi acetic acid dihydroximate in DVBS (IDAAH-DVBS), have been synthesized and their various physicochemical characteristics studied. The degree of retention of metal ions by the resins at equilibrium has been deter mined in terms of the molar distribution coefficient (K-d). In general , the resins having a dihydroximate moiety are found to be more effici ent compared to monohydroximate resins. However, it is of interest to note that the monohydroximate derivative of amino acid (GH-DVBS) showe d better metal retention capability than the dihydroximate of carboxyl ic acid (MAH-DVBS). The selectivity of the resins for transition and h ighly charged metal ions is quite high compared to that for alkaline e arth metals. All the synthesized resins can be utilized for the separa tion of a mixture of metal ions because the differences in the distrib ution coefficient values are large enough to permit good separations o n columns. However, the GH-DVBS resin was tried for the separation of copper-cobalt and copper-nickel mixtures at pH 5.5 using the column mo de of operation.