A designable magnetic MOF composite and facile coordination-based post-synthetic strategy for the enhanced removal of Hg2+ from water

A magnetic MOF composite was successfully prepared by a novel and green strategy through reasonable design. The nano Fe3O4@SiO2 core was first coated by a shell of Cu(OH)(2) as the self-template, followed by a conversion of Cu(OH)(2) into HKUST-1 at room temperature in a water-ethanol mixture solvent, and Fe3O4@SiO2@HKUST-1 core-shell nanostructures were obtained successfully. Based on this, a Bi-I-functionalized-magnetic HKUST-1 composite was prepared through a flexible coordination-based postsynthetic strategy. Powder X-ray diffraction spectrometry, N-2 sorption-desorption isotherms and Fourier transform infrared spectroscopy were used for the characterization of the magnetic MOF composites. The core-shell morphology was confirmed by transmission electron microscope images and the result of thermogravimetric analysis showed that the magnetic composites had excellent thermal stability. Besides, the adsorption of Hg2+ on Fe3O4@SiO2, Fe3O4@SiO2@HKUST-1 and Bi-I-functionalized magnetic MOF composites was investigated, and a good adsorption selectivity of Bi-I-functionalized magnetic MOF composites towards Hg2+ was demonstrated, with high adsorption capacity (264 mg g(-1)) and fast adsorption dynamics. The Bi-I-functionalized magnetic HKUST-1 composite was then successfully employed for the selective removal of Hg2+ from water, demonstrating great potential application of the prepared magnetic MOF composite as a fascinating adsorbent in environmental monitoring.