Authors: Fatemeh Yazdiamiri | Heshmatollah Alinezhad | Ameneh Kiani | Shahram Ghasemi
Source: Scientific Reports (article, 2025-10-24)
Field: Chemistry — Inorganic Chemistry

Zr-MOF-glutaraldehyde-Adn@Fe3O4 nanocomposite: as a new adsorbent for removal of methylene blue and heterogeneous nanocatalyst for the synthesis of tetrahydrobenzo[b]pyran derivatives In this research, a magnetic hybrid material (Zr-MOF-glutaraldehyde-Adn@Fe<sub>3</sub>O<sub>4</sub>) consisting of UiO-66-NH<sub>2</sub> as a stable and unique metal-organic framework, and Fe<sub>3</sub>O<sub>4</sub> nanoparticles was synthesized. Firstly, a highly stable zirconium-based UiO-66-NH<sub>2</sub> metal-organic framework (Zr-MOF) was modified with glutaraldehyde and subsequently with the green ligand of adenosine (And) to introduce functional groups containing N and O atoms on the surface. Secondly, Fe<sub>3</sub>O<sub>4</sub> nanoparticles were successfully stabilized into functionalized MOF named Zr-MOF-glutaraldehyde-Adn to form Zr-MOF-glutaraldehyde-Adn@Fe<sub>3</sub>O<sub>4</sub> nanocomposite. Vibrating sample magnetometer (VSM) analysis disclosed a saturation magnetization of Zr-MOF-glutaraldehyde-Adn@Fe<sub>3</sub>O<sub>4</sub> was acquired to be 34.76 emu/g, clearly indicates to good magnetic properties of prepared nanocomposite. The performance of Zr-MOF-glutaraldehyde-Adn@Fe<sub>3</sub>O<sub>4</sub> nanocomposite as a new adsorbent in the adsorption of methylene blue (MB) and a heterogeneous catalyst in the synthesis of tetrahydrobenzo [b]pyrans derivatives was evaluated. In the removal process of MB dye, the optimization parameters related to the initial pH (3-9), quantity of adsorbent (5-20 mg), initial concentration of analyte (10-40 mg/L), and contact time (2-20 min) of the solution were defined, and tests related to equilibrium isotherms and adsorption kinetics were investigated. The Langmuir isotherm (R<sup>2</sup> = 0.99) and pseudo-second-order kinetics model (R<sup>2</sup> = 0.99) exhibited well interpretation of the adsorption experiment outcomes. The results indicated that the maximum capacity adsorption of MB using Zr-MOF-glutaraldehyde-Adn@Fe<sub>3</sub>O<sub>4</sub> was 62.5 mg/g. In addition, Zr-MOF-glutaraldehyde-Adn@Fe<sub>3</sub>O<sub>4</sub> demonstrated excellent efficiency in the synthesis of substituted tetrahydrobenzo [b]pyrans scaffolds in H<sub>2</sub>O as a safe, available, and ideal solvent. The great adsorptive performance, using green solvent, short reaction time, high conversion, and reusability of the catalyst are some of the notable features of the proposed multifunctional nanocomposite. The novelty of the current research relies on the development and exploration of the multi-application of the designed Zr-MOF-glutaraldehyde-Adn@Fe<sub>3</sub>O<sub>4</sub> nanocomposite as an efficient sorbent for the easy purification of wastewater and a heterogeneous catalyst towards the synthesis of tetrahydrobenzo [b]pyrans derivatives. Adsorption ; Glutaraldehyde ; Methylene blue ; Catalysis ; Langmuir adsorption model ; Nanocomposite ; Kinetics ; Isatin Metal-Organic Frameworks: Synthesis and Applications ; Adsorption and biosorption for pollutant removal ; Nanomaterials for catalytic reactions