Magnetic molecularly imprinted polymer nanoparticles for separating aromatic amines from azo dyes - Synthesis, characterization and application

摘要

In order to improve the tedious pretreatment process of the detection of aromatic amines, a new material based on magnetic molecular imprinting technology which could specifically recognize 4,4'-Methylene bis(2-chloroaniline) and perform rapid enrichment was prepared. MIPs were synthesized on the surfaces of the magnetic silica gel spheres via thermal initiations using 2-Vinylpyridine as the functional monomer, ethylene glycol dimethacrylate as the cross-linker and 2,2'-azo-bis-isobutyronitrile as the initiator. Fourier transform infrared spectroscopy, transmission electron microscope, nitrogen sorption measurement and magnetic characterization were used to characterize the MIPs. The adsorption kinetic curve, adsorption isotherm and selective adsorption were measured by a static method. The results showed that the adsorption reached equilibrium in about 30 min and the maximum adsorption capacity was 6.31 mu mol/g. In addition, the adsorption process fitted well to a pseudo-second order model and the equilibrium data fitted to a Freundlich equation. The method with molecularly imprinted polymer was evaluated by the blank sample spiked with MOCA by UV-vis absorption spectra. The average recovery was in the range of 82.36-87.53% with RSD value lower than 9.07%. These results prove that this new method is effective in the rapid detection of the carcinogenic aromatic amine released from azo dyes.