Achieving high-efficient photocatalytic persulfate-activated degradation of tetracycline via carbon dots modified MIL-101(Fe) octahedrons

The synergistic reaction of photocatalysis and advanced oxidation is a valid strategy for the degradation of harmful antibiotic wastewater. Herein, carbon dots (CDs) modified MIL-101(Fe) octahedrons to form CDs/MIL-101(Fe) composite photocatalyst was synthesized for visible light–driven photocatalytic/persulfate(PS)-activated tetracycline(TC) degradation. The electron spin resonance (ESR) spectra, scavenging experiment and electrochemical analysis were carried out to reveal that the high visible light–driven photocatalytic degradation activity of TC over CDs/MIL-101(Fe) photocatalysts is not only ascribed to the production of free active radicals in the CDs/MIL-101(Fe)/PS system (·OH, ·SO4−, 1O2, h+ and ·O2−) but also attributed to the consumption of electrons caused by the PS, which can suppress the recombination of photo-generated carriers as well as strong light scattering and electron trapping effects of CDs. Finally, the possible degradation pathways were proposed by analyzing intermediates via liquid chromatography–mass spectrometry technique. This research presents a rational design conception to construct a CDs/PS-based photocatalysis/advanced oxidation technology with high-efficient degradation activity for the remediation of organic antibiotic pollutant wastewater and for the improvement of carrier transport kinetics of photocatalysts.