NiFe2O4 magnetic nanoparticles supported on MIL-101(Fe) as bimetallic adsorbent for boosted capture ability toward levofloxacin

Abstract

Levofloxacin (LVX) capture with microcrystalline particles of monometallic metal-organic frameworks (MOFs) is definitely restricted and challenged by its difficulties in solid-liquid separation and enhanced of adsorption capacity issues. Meanwhile, the development of magnetic MOFs with excellent adsorption capabilities and outstanding recyclability is crucial. Herein, a novel magnetic Fe/Ni bimetal MOFs composite (MIL-101(Fe)@NiFe2O4, MNFO) for LVX capture has been effectively fabricated for LVX capture, utilizing MIL-101(Fe) as the primary adsorbent and NiFe2O4 nanoparticles as the magnetic element. Attributed to the synergistic ability of bimetal ions (Fe2+ and Ni2+), MNFO exhibits a significant adsorption capacity (335 mg/g) and rapid adsorption rate (10 min) towards LVX. The adsorption capacity indicates an increasing-then-decreasing trend with an increase of the pH values. Additionally, the adsorption data are well fitted by the Freundlich and pseudo-second-order kinetic models. Thermodynamic studies indicated that the adsorption process was spontaneous and endothermic. In addition, the adsorbent demonstrated excellent reusability, as it could be readily recovered from the liquid phase through the magnetic properties of NiFe2O4. Remarkably, it retained approximately 90 % of its adsorption capacity of the uptakes after 5 cycles. This study offers a innovative approach to the development of highly efficient adsorbents for capturing LVX from water.