ABSORPTION RELEASE OF POLYVALENT METAL-IONS BY A POLYELECTROLYTE GEL/

The swelling/contraction dynamics of a strongly charged gel immersed i n a copper sulphate solution were studied. Changes in the size of the gel particle and the penetration of metal ions inside the network were monitored by optical microscopy. The equilibrium state was attained i n two steps: First, the gel swells, mainly by absorbing water, and the n it collapses, to the almost dry state. The release of copper ions fr om the contracted gel when it was placed in acidic medium was studied as a function of time using optical microscopy. The influence of the a cid concentration on the rate of ion release and on changes in the par ticle size of the gel are discussed. (C) 1998 Elsevier Science B.V. Al l rights reserved.