Magnetic molecularly imprinted polymers based on attapulgite/Fe3O4 particles for the selective recognition of 2,4-dichlorophenol

Via encapsulation of attapulgite/Fe3O4 magnetic particles (ATP/Fe3O4), the magnetic molecularly imprinted polymers (MMIPs) were synthesized for the selective recognition of 2,4-dichlorophenol (2,4-DCP). MMIPs were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) analysis, thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), nitrogen adsorption-desorption analysis and Raman spectroscopy. MMIPs were demonstrated claviform shape with an imprinted polymer film (thickness of about 16 nm), and exhibited magnetic property (M-s = 5.67 emu g(-1)) and thermal stability. Batch mode adsorption studies were carried out to investigate the specific binding capacity, binding kinetics and recognition specificity. The Langmuir isotherm model was fitted to the equilibrium data better than the other models, and the monolayer adsorption capacity of MMIPs were 145.79 mg g(-1) at 298 K. The kinetic properties of MMIPs were well described by the pseudo-second-order equation, initial adsorption rate and half-adsorption time. The selective recognition experiments demonstrated high affinity and selectivity towards 2,4-DCP over structurally related phenolic compounds. In addition, MMIPs could be regenerated, and their adsorption capacity in the fifth use was about 7.53% loss in 2,4-DCP solution. The MMIPs as-prepared were successfully applied to the separation of 2,4-DCP from environmental water samples. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.