Removal of a mixture of antibiotics in water using nonthermal plasma

A dielectric barrier discharge with falling liquid film was used to degrade the antibiotics amoxicillin and sulfamethoxazole in water. The antibiotic concentrations decrease exponentially during plasma treatment and have similar half-life time, in the range 4-9 min. By increasing the discharge power (9.1-20.2 W), faster removal of the contaminants is obtained, but the energy efficiency remains almost the same, 3-4 g/kWh at 50%. Oxygen considerably improves the energy yield by a factor of two as compared with air, due to more effective formation of reactive oxygen species. It was found that the degradation of antibiotics in mixture essentially depends on the overall initial concentration, this behavior being attributed to the similar reactivity of the two investigated compounds.