Synthesis and Characterization of a Molecularly Imprinted Polymer for Methylene Blue

Saliza Asman, Nor Azah Yusof*, Abdul Halim Abdullah and Md. Jelas Haron

Chemistry Department, Faculty of Science, University Putra Malaysia, 43400 Serdang, Selangor, Malaysia *Corresponding author: E-mail: azah@science.upm.edu.my

Abstract

This study reports the preparation of a molecularly imprinted polymer for the removal of methylene blue dye from aqueous media. The methylene blue-molecularly imprinted polymer was prepared using bulk polymerization via radical polymerization containing methylene blue as a template, methacrylic acid, as a monomer, ethylene glycol dimethacrylate as a cross-linker, benzoyl peroxide as an initiator and tetrahydrofuran as a solvent (porogen) in ratios of 0.117 mmol, 0.930 mmol, 4.650 mmol, 10.000 mg and 30.000 mL, respectively. The polymer block obtained was ground and sieved using a 90 μm sieve and the methylene blue template was removed from the methylene blue-molecularly imprinted polymer by extracting it with methanol/ acetic acid/water (8:1:1) mixture. The non-molecularly imprinted polymer was synthesized as a reference. The methylene blue-molecularly imprinted polymer was characterized by using Fourier-transform infrared spectroscopy, scanning electron microscopy, a particle size analyzer and BET equation. The effect of different parameters such as pH, time and concentration of methylene blue, selectivity and reusability of the methylene blue-molecularly imprinted polymer were evaluated. Maximum sorption of methylene blue occurred at pH 5 in 30 s. The sorption followed a pseudo-second-order kinetic model. The adsorption isotherm of methylene blue followed the Freundlich isotherm model. The selectivity study had proved that the methylene blue-molecularly imprinted polymer was highly selective to the methylene blue analyte.

Keywords

Molecularly imprinted polymer, Methylene blue, Bulk polymerization, Reusability, Selectivity.

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  • Asian J. Chem. /
  •  2011 /
  •  23(11) /
  •  pp 4786-4794