UiO-66-based metal organic frameworks for the photodegradation of acetaminophen under simulated solar irradiation.

This work reports the solvothermal synthesis of UiO-66-based MOFs with three different ligands and its application to the breakdown of aqueous acetaminophen under simulated sunlight. This pharmaceutical is a representative contaminant of emerging concern that enters water bodies mainly through wastewater treatment plant discharges. The synthesis approach of the MOFs was fitted using a zirconium alkoxide as metal cluster precursor and 2-aminoterephthalic and 2,5-dihydroxyterephthalic acids as ligands to prepare UiO-66-NH 2 and UiO-66-(OH) 2 MOFs, respectively. These new MOFs have enhanced visible light harvesting and narrower band gap than the UiO-66. Among all, UiO-66-NH 2 yielded the highest removal of acetaminophen under simulated solar irradiation in batch test. The activity and stability of UiO-66-NH 2 were demonstrated for the first time in a continuous flow test, where stable performance was observed upon 30 h on stream. The degradation pathway of acetaminophen was elucidated based on coupling, ring-opening, and oxidation reactions. DFT calculation confirmed that the indirect semiconductor behavior of UiO-66-NH 2 upon light excitation occurred through ligand-ligand charge transfer. Overall, promising UiO-66-based MOFs photocatalysts were obtained for effective degradation of acetaminophen with the assistance of solar light. [Display omitted] • Solvothermal method was used to synthesize UiO-66-based MOFs with narrow bandgaps. • Aqueous acetaminophen was effectively removed using simulated solar radiation. • UiO-66-NH 2 works in a continuous system. • The degradation pathway of acetaminophen was elucidated in this study. • UiO-66-NH 2 acts as indirect semiconductor through ligand-ligand charge transfer. [ABSTRACT FROM AUTHOR]