Metal adsorption behaviour of the microspheres

The metal adsorption behaviour of the non-imprinted and Cu(II)-, Ni(ll)- and Co(II)-imprinted microspheres was examined at pH 5.6 [15]. The adsorption was expressed as the percentage of metal ions adsorbed on the resin with respect to the total amount of metal ions originally added to the solution (Table 9.1). 

First of all, Cu(II) was most effectively adsorbed by Cu(II)-imprinted microspheres, followed by non-imprinted, Ni(II)-imprinted and Co(II)-imprinted microspheres. This sequence clearly verified the effect of Cu(II) imprinting the carboxylate groups and the polymer chains that carry them are placed on the Cu(II)-imprinted microsphere surface in such a way that they match the square planar coordination around the Cu(II) ion. 

As for Ni(Il) adsorption, only Cu(ll)- and Ni(II)-imprinted microspheres exhibited a binding affinity under the described adsorption conditions the adsorption was higher for Ni(II)-imprinted microspheres (17%) than for Cu(II)-imprinted microspheres (7%). This, again, clearly indicated the effect of imprinting. 

The Ni(II)-imprinted microspheres were characterised by the Ni(II) binding affinity, which exceeded the affinity to the Cu(II)-imprinted microsphere. This was in contrast to the Irving-Williams series. In order to confirm this surprising result, a Ni(II)-imprinted microsphere was prepared in duplicate and it was found that the two preparations gave almost identical results preparation 1, 14% for Cu(II) and 17% for Ni(II) preparation 2, 13% for Cu(II) and 18% for Ni(II). It is emphasised that the results all came from the difference in the spatial disposition of the 

PERCENTAGE ADSORPTION OF SINGLE METAL ION SPECIES ONTO NON-IMPRINTED AND METAL ION-IMPRINTED MICROSPHERES  

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