Round-the-clock degradation of pharmaceutical pollutants by photocatalytic and catalytic ozonation based on bifunctional MIL-100(Fe) catalyst.

Pharmaceutical contaminants in aquatic environments pose significant ecological and health risks, necessitating innovative and sustainable degradation technologies. This study presents a round-the-clock catalytic system utilizing bifunctional MIL-100(Fe) for the efficient degradation of ketoprofen (KTP) and real pharmaceutical wastewater through photocatalytic ozonation (PCO) and catalytic ozonation (CO). The MIL-100(Fe) catalyst was synthesized via an HF-free hydrothermal method using FeSO4 as the metal source, exhibiting high crystallinity, hierarchical porosity, visible-light responsiveness and efficient charge transfer. The PCO/CO system achieved 92.6 % KTP degradation within 60 min in the dark and nearly complete removal (100 %) under visible light irradiation. For actual pharmaceutical wastewater, chemical oxygen demand (COD) removal efficiencies of 77.4 % (PCO) and 73.4 % (CO) were attained at 120 min, meeting stringent discharge standards. Remarkably, MIL-100(Fe) maintained robust stability during 12-hour continuous operation, retaining >65 % COD removal efficiency. Mechanistic studies revealed that Lewis acid sites of Fe ions and photogenerated electrons drive ozone decomposition, generating •OH, •O2-and 1O2 responsible for pharmaceuticals degradation. Density functional theory (DFT) calculations elucidated dual ozone activation pathways: direct interaction with Fe(III) sites and indirect interaction with Fe(III)-OH sites​, both facilitated by Fe(II)/Fe(III) cycling. Intermediate analysis and toxicity assessment confirmed the degradation pathways and reduced ecological risks of intermediates. This work advances scalable and energy-efficient solutions for continuous pharmaceutical pollutant removal based on PCO and CO over bifunctional MIL-100(Fe).