Magnetism-induced structural defects in MOF-based adsorbents for the highly efficient capture of diclofenac sodium

Engineering structural defects into metal–organic frameworks (MOFs) offer a promising strategy to modulate their porosity and enhance adsorption performance. In this study, we report the synthesis of a novel magnetic porous adsorbent, designated as DLU-1 (DLU, Dali University), featuring hierarchical pore structures. For comparison, the reference sample, pristine UiO-66-NH 2 , was synthesized without defect modulation. Nitrogen adsorption–desorption isotherm analyses revealed that DLU-1 exhibits a significantly larger surface area (745.60 m 2 /g) than pristine UiO-66-NH 2 (311.82 m 2 /g), which is attributed to the presence of structural defects and microporosity. DLU-1 was demonstrated outstanding performance in the removal of diclofenac sodium (DS), achieving a maximum adsorption capacity of 387.92 mg/g at 298 K based on Langmuir isotherm modeling—substantially surpassing pristine UiO-66-NH 2 (83.29 mg/g) and many previously reported MOF-based adsorbents. Moreover, the magnetic characteristics enable DLU-1 to be efficiently separated from aqueous solutions using an external magnetic field. The DLU-1 also exhibited excellent reusability, with negligible loss in adsorption efficiency after three regeneration cycles. This work highlights the synergistic advantages of structural defect engineering and magnetic functionalization in MOFs, offering a viable strategy for the development of high-performance adsorbents for pharmaceutical wastewater treatment.