Simultaneous removal of levofloxacin and sulfadiazine in water by dielectric barrier discharge (DBD) plasma: Enhanced performance and degradation mechanism

Antibiotics are abused and discharged into environmental water, posing a constant potential threat to ecosystem. It is still a challenge to treat the wastewater containing various antibiotics. While many studies have reported the plasma treatment of different antibiotics, how to treat multiple antibiotics simultaneously with high efficiency still remains an unsolved problem. In this work, we employed atmospheric-pressure dielectric barrier discharge (DBD) to treat levofloxacin and sulfadiazine as two typical antibiotics in water, and investigated the treatment efficiency and the involved mechanism. The experimental results indicated that under proper conditions, the total antibiotics removal efficiency could be enhanced compared to separate single antibiotic treatment. The contributions from the plasma-induced reactive oxygen/nitrogen species (RONS) were examined, showing that ·OH played a major role in levofloxacin degradation, while ozone and peroxynitrite also played a certain role in sulfadiazine degradation. The bio-toxicity evaluation for the plasma treatment of levofloxacin and sulfadiazine was also provided, showing that the DBD degradation products were harmless to the ecological environment. As such, this work may not only provide a practical solution to treatment of wastewater containing multiple antibiotics, but also give the insights into the mechanism for the efficient DBD treatment of mixed antibiotics in wastewater.