Removal of estrogenic pollutants from contaminated water using molecularly imprinted polymers

A synthetic molecularly imprinted polymer (MIP) sorbent for estrogenic compounds was prepared using a noncovalent imprinting technique. MIP microspheres sized from 1 to 2 μm were synthesized in acetonitrile by using α-estradiol as the template, acrylamide as the functional monomer, and trimethylpropanol trimethacrylate as the cross-linker. When compared with the nonimprinted polymer (NIP), the MIP showed outstanding affinity toward α-estradiol in aqueous solution with a binding site capacity (B _max) of 380 nmol mg^-1 MIP, imprinting effect of 35, and a dissociation constant (K_d) of 38 μM. The MIP exhibited significant binding affinity toward other related estrogenic compounds such as β-estradiol, diethylstilbestrol, estriol, and estrone, suggesting that this material may be appropriate for treating a complex mixture of estrogenic pollutants. The feasibility of removing estrogenic compounds from environmental water by the MIP was demonstrated using lake water spiked with α-estradiol. In addition, the MIP reusability without any deterioration in performance was demonstrated for at least five repeated cycles.