Magnetic montmorillonite functionalized with UiO-66 metal-organic framework as a hierarchical adsorbent for magnetic solid-phase extraction of polycyclic aromatic hydrocarbons.

A novel hierarchical magnetic nanocomposite, MMT/Fe3O4/UiO-66, was synthesized by functionalizing magnetized montmorillonite with the zirconium-based metal-organic framework UiO-66 and evaluated as an adsorbent for the magnetic solid-phase extraction (MSPE) of four polycyclic aromatic hydrocarbons (PAHs): naphthalene, 2-methylnaphthalene, fluorene, and anthracene. The material combines the magnetic separability of Fe3O4, the layered structure of montmorillonite, and the high porosity of UiO-66, providing enhanced surface area for PAH enrichment. Under optimized MSPE conditions, the method showed wide linear ranges (0.01-500 ng mL-1 for naphthalene and 2-methylnaphthalene; 0.03-200 ng mL-1 for fluorene and anthracene), low limits of detection (0.003-0.01 ng mL-1), and good precision (RSD = 4.1-5.5%). The method was successfully applied to drinking, river, and well water samples, achieving high relative recoveries (98.1-99.6%). The results demonstrate that the MMT/Fe3O4/UiO-66 nanocomposite is a promising, sustainable sorbent for the efficient monitoring of trace PAHs in environmental waters, offering a practical alternative to conventional extraction materials.