Degradation of veterinary antibiotics by dielectric barrier discharge plasma

This work investigated the degradation of antibiotics in synthetically prepared wastewater by using dielectric barrier discharge (DBD) plasma. The veterinary antibiotics investigated include lincomycin, ciprofloxacin, enrofloxacin, chlortetracycline, oxytetracycline, sulfathiazole, sulfamethoxazole, sulfamethazine and trimethoprim. The effect of discharge power, initial concentration, working gas type (air or O2) and working gas flow rate on the degradation was examined and discussed. The experimental results indicated that the antibiotics were easily degraded by the DBD plasma and the degradation rates were mainly governed by the amount of the delivered energy. The degradation of the antibiotics followed an exponential decay with respect to the delivered energy. Each antibiotic substance was found to show a different degradability. On the basis of an initial concentration of 5 mg L−1, the energy requirements for 60% degradation efficiency were in the range of 0.26–1.49 kJ mg−1, depending on the type of antibiotic substance, while those for 90% degradation efficiency ranged from 0.39 to 2.06 kJ mg−1. The DBD process proposed in this work may be a promising method for effectively degrading veterinary antibiotics.

► The plasma method is very energy-efficient for degrading antibiotics.
► The degradation followed exponential decay with respect to the delivered energy.
► Each antibiotic substance shows a different degradability in the plasma reactor.