Publication: Microwave enhanced synthesis of chitosan-graft-polyacrylamide molecular imprinting polymer for selective removal of 17?-estradiol at trace concentration
Date
2011
Authors
Saifuddin N.
Nur Y.A.A.
Abdullah S.F.
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Abstract
Polymers have been molecularly imprinted for the purpose of binding specifically to 17?-estradiol. A molecularly imprinted polymer (MIP) material was prepared using 17?-estradiol as the imprinted molecule, acrylamide as functional monomer and macroporous chitosan beads as functional matrix. Chitosan-graft-polyacrylamide was synthesized without any radical initiator or catalyst using microwave (MW) irradiation, which allowed MIP production in about 1 h compared to conventional method which requires 8-10 h. The representative microwave synthesized graft copolymer was characterized by Fourier transform-infrared spectroscopy, taking chitosan as a reference. The parameters studied included MIP synthesis optimization, using microwave, adsorption kinetics, adsorption isotherm, selectivity and reusability. Batch as well as column flow studies were performed. Removal experiments in batch were carried out by applying the chitosan-graft-polyacrylamide Molecular Imprinting Polymer (MIP) to various 17?-estradiol aqueous solutions. The chitosan coated polyacrylamide MIP was more rigid with better stability and enhanced adsorption capacity. The maximum adsorption capacity was observed to be 5.01 mg g-1 of MIP, which gave removal efficiency of above 91%. After 60 min, the change of adsorption capacities for 17?-estradiol did not show notable effects. The Langmuir and Freundlich adsorption models were also applied to describe the equilibrium isotherms. Equilibrium adsorption data showed that the adsorption of 17 ?-estradiol onto the MIP fitted well to the Langmuir equation. The MIPs were easily regenerated after each experiment with Methanol:Acetic acid (4:1 v/v) solvent and reused. � 2011 Academic Journals Inc.
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Keywords
Adsorbent , Freundlich isotherms , Langmuir isotherm , Micropollution , Wastewater