Metal-Organic Framework@Carbon Hybrid Magnetic Material as an Efficient Adsorbent for Pollutant Extraction

The preparation of a hybrid magnetic metal-organic framework (MOF)@carbon from a MOF-derived porous carbon is reported. MOF-74(Co) is used as a precursor for the synthesis of a magnetic carbon with homogeneous cobalt particle distribution (C-MOF-74) by a direct carbonization step. The cobalt particles present in the carbon are partially converted to zeolitic imidazolate framework (ZIF)-67 by reaction with 2-methylimidazole to obtain a core-shell ZIF-67@C-MOF-74. The effect of the reaction time and 2-methylimidazole concentration in the conversion procedure is studied by X-ray diffraction and scanning microscopy. Because of its high surface area, dual porosity, and magnetic properties, ZIF-67@C-MOF-74 exhibits high extraction capacity (180 mg g^-1), fast adsorption rate, and excellent recyclability for Congo red adsorption. In addition, the prepared material shows high efficiency in the extraction of different phenolic compounds. The developed procedure can be easily adapted to different carbons and MOFs, thus potentially enabling the preparation of a wide number of new hybrid materials.