Preparation of Magnetic Dummy Molecularly Imprinted Meso-Porous Silica Nanoparticles Using a Semi-Covalent Imprinting Approach for the Rapid and Selective Removal of Bisphenols from Environmental Water Samples

Abstract

Bisphenol compounds (BPs) are a severe threat to humans and creatures; hence it is critical to develop a quick and simple approach for removing trace BPs from water. This research synthesized a novel template–monomer complex, phenolphthalein-(3-isocyanatopropyl)triethoxysilane (PP-ICPTES), as a dummy template, and a molecularly imprinted polymer for bisphenol was made via a semi-covalent approach. By successfully coating the imprinted layer on the Fe3O4@SiO2@mSiO2 structure, a magnetic dummy molecularly imprinted mesoporous silica nanoparticles (m-DMI-MSNPs) with a core-shell structure and superefficient aqueous phase selectivity for bisphenols was synthesized. The morphology and structure of the m-DMI-MSNPs were characterized using transmission electron microscopy (TEM), nitrogen adsorption-desorption analysis, Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometry (VSM). The prepared m-DMI-MSNPs presented excellent water compatibility and magnetic separation abilities. The m-DMI-MSNPs showed excellent recognition selectivity towards BPs with imprinting factors of 7.6, 8.2, and 7.5 for bisphenol F (BPF), bisphenol E (BPE), and bisphenol A (BPA), respectively. Fast binding kinetics (equilibrium time < 1 min) and a high rebinding capacity (maximum adsorption capacity, 38.75 mg g–1) were observed in the adsorption experiments. More importantly, the m-DMI-MSNPs, which combine good water compatibility, class selectivity, and magnetic separation performance, exhibited excellent performance for the removal of BPF, BPE, and BPA from tap water, mineral water, and sewage water samples, with removal efficiencies in the ranges of 96.6–97.8, 95.6–97.1, and 93.1–95.3%, respectively.