Selective ion exchangers from cross-linked alginate

Alginate crosslinking with epichlorohydrin Ieads to the formation of chelating selective cation exchangers, since it insolubilises the polymer even in the basic field with no marked impairment of the exchange and swelling properties. Exchangers with different properties were obtained on varying the preparation technique. Crosslinking of a sodium alginate powder was used to prepare a microgranular resin. This gave quantitative results in the separations of Ni2+/Cu2+, Co2+/Cu2+ and Ca2+/Ba2+ by column exchange chromatography. Its excessive swelling in basic media made this exchanger unsuitable for use in arnmonia solution. When preformed calcium alginate beads were crosslinked, exchangers suitable for column operation in basic media were obtained. Exchange tests with Cu2+ and Ni2+ complexes were performed.