Effective photodegradation of rhodamine B and levofloxacin over CQDs modified BiOCl and BiOBr composite: Mechanism and toxicity assessment

In this contribution, carbon quantum dots (CQDs) modified 3D-flower like BiOX (X = Cl, Br, I) photocatalyst were successfully prepared via a facile mechanical compounding method. The crystal structure, surface composition, morphologies, optical properties and photocatalytic activities were investigated in detail. The photocatalytic activity of the as-obtained photocatalyst were evaluated by degradation of rhodamine B (RhB) and Levofloxacin (LEV) under near IR-UV-vis light irradiation, the CQDs/BiOX composite displayed enhanced photocatalytic activity as compared with individual BiOX materials. The CQDs/BiOX composite had the outstanding light harvesting and electron transfer ability because of the ordered ultrathin nanosheet structure of the BiOX, the formation of metal Bi under photoinduction, and the synergistic effects between CQDs and pure BiOX. Antibacterial activity and effects on Rye seeds growth of the LEV degradation intermediate were also researched. Reactive-species-trapping experiments exhibited that h+ and O2- were the active reactive species during photodegradation process. This work provided an effective and simple strategy for designing QDs modified Bi-rich oxyhalides in organic pollutant containing wastewater treatment.