Removal of bisphenol A in aqueous solutions by core-shell magnetic molecularly imprinted polymers

This paper reports the preparation of surface-imprinted polymer core-shell magnetic material as adsorbent for separating bisphenol A in the environmental water. The adsorbent prepared easily achieved the magnetic separation under an external magnetic field. The structures of the resulting composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) analysis. The adsorption selectivity of Fe3O4@SiO2-MIPs for bisphenol A was demonstrated by equilibrium rebinding experiments and Scatchard analysis. Freundlich adsorption model can well describe the adsorption isothermals of bisphenol A with the correlation coefficients R2 = 0.995 2. The dynamics of bisphenol A adsorbed by Fe3O4@SiO2-MIPs can be well described by the pseudo second-order model (R2 = 0.999 9). In the solutions with weak acidity, the Fe3O4@SiO2-MIPs showed higher removal rate and rapid adsorption dynamical process, requiring only 40 min to reach a removal rate of 90%; the presence of ions did not affect the adsorption rate of bisphenol A; when compared with the non-imprinted polymer (Fe3O4@SiO2-NIPs), the Fe3O4@SiO2-MIPs showed outstanding affinity toward bisphenol A; the performance of the resulting composites (Fe3O4@SiO2-MIPs) without obvious deterioration was demonstrated in seven repeated cycles.