Fabrication of magnetic trimetallic metal–organic frameworks for rapid removal of tetracycline from water

MOF-74 series is characteristic by the most open metal sites. The metal ions have different bonding strengths with the ligand in MOF-74 and can be successively broken with the bond of the ligand to obtain highly active heteroparticles by controlling the temperature, which are difficult to achieve by traditional methods. The magnetic NiCo/Fe3O4-MOF-74 which fabricated by using trimetallic NiCoFe-MOF-74 as precursor is simple and rational in compare with the traditional magnetic core and tunable MOF shell hybrid composites that are known as step-by-step assembly strategy. After thermal treatment under specific atmosphere, the NiCo/Fe3O4-MOF-74 shows higher stability, strong magnetism and more active metal sites compared to the original MOF. The NiCo/Fe3O4-MOF-74 shows an excellent enrichment capability to tetracycline with high removal efficiency reached 94.1% within 5 min, which is much higher than that of NiCoFe-MOF-74. The main interaction between adsorbent and analyte was most likely attributed that the open metal sites can be formed stable metal-ligand with antibiotic molecules. Besides, the material can be reused 5 times without considerable loss. The prepared material has potential applications for removing antibiotics with high efficiency and low cost. Therefore, the experiments described provide a route to a broad class of MOF-based materials for detecting organic contaminant.