Properties of magnetic microbeads in removing bisphenol-A from aqueous phase

In this study, magnetic poly(ethylene glycol dimethacrylate-N-methacryloyl-l-tryptophan methyl ester) [m-poly(EGDMA-MATrp)] beads (average diameter = 53-103 mu m) were synthesized by copolymerizing of N-methacryloyl-l-tryptophan methyl ester with ethylene glycol dimethacrylate in the presence of magnetite (Fe3O4) and used for removal of bisphenol-A (BPA). The m-poly(EGDMA-MATrp) beads were characterized by N-2 adsorption/desorption isotherms (BET), X-ray photoelectron spectroscopy, scanning electron microscopy, infrared spectroscopy, thermal gravimetric analysis, electron spin resonance analysis and swelling studies. To evaluate the efficiency of m-poly(EGDMA-MATrp) beads for adsorption of BPA from aqueous medium, the effects of pH, initial concentration, contact time and temperature were analyzed. The maximum BPA adsorption capacity of the m-poly(EGDMA-MATrp) beads was determined as 139.6 mg/g at pH 5.0, 25 A degrees C. All the isotherm data can be fitted with the Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The adsorption process obeyed pseudo-second-order kinetic model.