MULTISWEEP CYCLIC VOLTAMMETRIC STUDIES ON THE EFFECT OF CHARGE ON DIFFUSION AND SORPTION PROCESSES OF ML(3)(N-MODIFIED ELECTRODES() CHELATES AT CLAY)

The unique pattern of uptake of Cr(bpy)(3)(3+) at clay-modified electr odes can be attributed to two factors as deduced from experiments with Co(bpy)(3)(3+), Co(bpy)(3)(2+), and(-)d-Cr(bpy)(3)(3+). In the first case, transport of the trivalent species is accelerated across the fil m because of electrostatic considerations. The initial swelling of the clay film controls the extent of accelerated transport through the fi lm by establishing the interlayer dimensions. Valence, however, does n ot completely control the pattern of loading of the clay film with the complex. Cr(bpy)(3)(3+) and Co(bpy)(3)(3+) exhibit different rates of adsorption by the clay surface which contribute to the differing non- equilibrium loading patterns.