KINETICS OF COMPLEXATION OF HEAVY-METAL IONS WITH POLYELECTROLYTES INAQUEOUS-SOLUTION

The kinetics of the binding of Ni2+ to polycarboxylate anions have bee n studied using pressure- and temperature-jump relaxation techniques. The reaction proceeds via the two-step Eigen mechanims: free ions form the outer-sphere and in the second step the inner-sphere complex. The outer-sphere complex is exceptionally stable due to the polyelectroly te effect, and the electrical potential at the polyelectrolyte surface is estimated to be psi approximate to-86 mV. The rate constant for th e formation of the inner-sphere complex is in the same range as that o btained for Ni2+ complexes with small anions. The formation of bidenta te complexes does not contribute significantly to the stability of the complexes. A parallel study Of the reactions of Ni2+ with malonate an d succinate has been performed.