Degradation of antibiotic contaminants from water by gas–liquid underwater discharge plasma

Antibiotic contamination adversely affects human health and ecological balance. In this study, gas–liquid underwater discharge plasma was employed to simultaneously degrade three antibiotics, sulfadiazine (SDZ), tetracycline (TC), and norfloxacin (NOR), to address the growing problem of antibiotic contaminants in water. The effects of various parameters on the antibiotic degradation efficiency were evaluated, including the discharge gas type and flow rate, the initial concentration and pH of the solution, and the discharge voltage. Under the optimum parameter configuration, the average removal rate of the three antibiotics was 54.0% and the energy yield was 8.9 g (kW·h)^-1 after 5 min treatment; the removal efficiency was 96.5% and the corresponding energy yield was 4.0 g (kW·h)^-1 after 20 min treatment. Reactive substance capture and determination experiments indicated that ·OH and O₃ played a vital role in the decomposition of SDZ and NOR, but the role of reactive substances in TC degradation was relatively less significant.