Photocatalytic Elimination of Moxifloxacin by Two-Dimensional Graphitic Carbon Nitride Nanosheets : Enhanced Activity, Degradation Mechanism and Potential Practical Application

AbstractsResiduals of antibacterial drugs (ADs) threaten human health and ecological equilibrium, whereas few efficient treatments have been developed. Herein a high-efficiency photocatalytic treatment was reported to eliminate moxifloxacin (MOX) as a fourth-generation quinolone, using a photocatalyst of two-dimensional (2D) g-C 3 N 4 nanosheets (CNNS) that was fabricated by ammonium chloride assisted chemical blowing method. Under the irradiation of visible light with a xenon lamp, the CNNS showed high photocatalytic activity for MOX elimination, which was 9.7 times the degradation rate constant of the bulky g-C 3 N 4 (BCN). The characterization results indicated that the high activity of CNNS originated from its 2D morphology, large specific surface area and high separation efficiency of photogenerated charges. Furthermore, the photocatalyst dosage, MOX concentration and the pH value of solution were optimized. Based on the detection of reactive oxygen species (ROS) and the intermediates during photocatalytic process, the plausible photocatalytic mechanism and the degradation pathways of MOX were proposed. The synthetic CNNS demonstrated excellent stability and reusability during the five cycles. Finally, we tested the photocatalytic MOX degradation performance by the CNNS in simulated real scenarios by using tap water, lake water and sunlight. The good activity suggested the CNNS had great potential for purifying ADs-containing wastewater