Construction of stable photo-Fenton system with efficient removal capability of ciprofloxacin by accelerating in-situ photoreduction of Fe 3+ in MIL-100(Fe)

Well-dispersed MIL-100(Fe) nanoparticles were synthesized under mild conditions and used to construct a photo-Fenton system (VMH system) with the assistance of visible-light irradiation and hydrogen peroxide. In such a VMH system, the MIL-100(Fe) has a high specific surface area and provides numerous Fe³⁺ active sites, thus accelerating the reaction of Fe³⁺ with photo-generated electrons under visible-light irradiation and generates Fe²⁺, and then the acquired Fe²⁺ can activate H₂O₂ to generate ⋅OH, accompanying with the oxidation of Fe²⁺ to Fe³⁺. Hence, the in-situ recycling of Fe²⁺/Fe³⁺ promotes the generation of ·OH, thus making the VMH system exhibits promising photocatalytic activity. The removal rate of ciprofloxacin in the VMH system is as high as 95.2% within 120 min photo-Fenton reaction, which is about 26 times higher than that of the Visible light/MIL-100(Fe) system. Moreover, the VMH system also exhibits strong degradation ability to other typical antibiotics, such as tetracycline, norfloxacin and cephalexin, and maintains high cyclic stability, revealing great practical application potential in the purification of antibiotic wastewater.