Adsorption of Diclofenac Sodium and 2, 4-Dichlorophenoxyacetic on Magnetic MIL-100(Fe) Composite Obtained at Room Temperature

Metal–organic frameworks (MOFs) have found a wide range of applications in the field of water treatment owing to their large specific surface area, well-developed cavities and abundant active centers. In this study, a magnetic MOF composite (Fe₃O₄/MIL-100(Fe)) was synthesized via a one-pot synthesis at room temperature, and its adsorption capacities towards diclofenac sodium (DS) and 2,4-dichlorophenoxyacetic acid (2, 4-D) were assessed. The maximum adsorption capacity of Fe₃O₄/MIL-100(Fe) was 249 mg·g^–1 for DS (pH 6.8, 313 K), whereas it was found to be 163 mg·g^–1 for 2, 4-D (pH 3.0, 293 K). Results from fitting isotherm models with the equilibrium data suggested that both the Langmuir and Koble–Corrigan models be suitable for describing the adsorption equilibrium data. Results from kinetic model analysis suggested that both the pseudo-second-order and double-constant model could describe the uptake of DS and 2, 4-D onto Fe₃O₄/MIL-100(Fe) well, respectively. The adsorption processes include both homogeneous physical and chemical adsorptions, such as electrostatic interaction, hydrogen bonding, and π–π interaction. Furthermore, Fe₃O₄/MIL-100(Fe) showed good regeneration and reusability, indicating that the synthesized adsorbent is highly efficient, relatively cost-effective, and stable.