2.5. Synthesis of ion-imprinted polymeric particles
The Zn(II)-imprinted particles were prepared by bulk polymerization
technique. In the first step, 4 mmol of 2-VP (functional
monomer) and 1 mmol of diphenylcarbazone (ligand) were
dissolved in 25 mL of methanol/dichloromethane (50:50) in a
100 mL glass flask. Subsequently, as the second step, 0.5 mmol of
Zn(NO3)2 as an imprinted metal ion (template) was added slowly
to a glass flask and the resulted mixture was stirred for 5 h at room
temperature. In the third step, 25 mmol of EGDMA and 0.3 mmol of
AIBN were added as cross-linker and initiator. The oxygen of the
sample solution was removed by bubbling nitrogen through the
sample for 10 min. Polymerization was performed in an oil bath at
65 8C for 24 h in the presence of nitrogen under magnetic stirring at
400 rpm. The prepared polymer was washed several times with
1:4 (v/v) methanol/water to remove the unreacted materials and
then with HCl 12% (v/v) for leaching the imprinted metal ions until
the washing solution was free from Zn(II) ions. Finally, it was
washed with double distilled water until it reached a neutral pH.
The resulting fine powder was dried under vacuum in a desiccator
before sorption and desorption studies. In the same way, the non
imprinted polymer (NIP) was also prepared without ions of zinc