Dielectric barrier discharge plasma combined with nano catalyst for aqueous amoxicillin removal: Performance modeling, kinetics and optimization study, energy yield, degradation pathway, and toxicity

[Display omitted] •The synthesized ZnO/α-Fe2O3 was used to degrade AMX in the DBD-catalytic process.•The combination of DBD with ZnO/α-Fe2O3 showed the highest AMX degradation efficiency.•The plasma-catalytic reaction process was optimized by RSM-BBD method.•The effluent toxicity of the ZnO/α-Fe2O3-DBD system was negative.•The intermediate products and possible degradation pathways were proposed. Dielectric barrier discharge (DBD) plasma has been increasingly used for degrading the emerging environmental pollutants. The UV–Vis irradiation and high energetic species produced by DBD plasma are two promising factors to couple DBD with catalysts in order to improve the degradation rate and reduce the production of harmful intermediates. Nowadays, searching to identify a powerful catalyst-plasma system for removing persistent pollutants is still an urgent need. Therefore, in the current study, a useful ZnO/α-Fe2O3 composite catalyst was synthesized using a low-temperature assisted co-precipitation method and was applied in combination with the DBD reactor for the degradation of amoxicillin (AMX), the antibiotic, in water. The morphology and structure of ZnO/α-Fe2O3 samples were characterized before and after the plasma DBD. In addition, the interaction effects among contact time, AMX initial concentration, composite catalyst loading, and solution pH on AMX degradation were assessed by the response surface method (RSM). Moreover, the performance evaluation, optimization, kinetics model, energy yield, degradation pathway, and toxicity of the plasma-catalysis process were studied. As a major result, the AMX degradation rate reached 99.3% during 18 min at the peak voltage of 15 kV, and ZnO/α-Fe2O3 load of 0.4 g L−1, AMX initial concentration of 16 mg L−1, and pH of 4.5 with a rate constant of 0.198 min−1, energy yield of 3 g kW−1 h−1, without any effluent toxicity. Finally, it can be concluded that the DBD- ZnO/α-Fe2O3 system exhibits a great and eco-friendly potential for aqueous AMX degradation.