Systematic evaluation and rational design of low-temperature atmospheric pressure microwave plasma jet for enhanced antibiotic degradation

Microwave plasma technology, particularly the three-layer coaxial low-temperature atmospheric pressure microwave plasma jet, offers a promising solution for pollutant degradation due to its electrode-free design and low microwave energy consumption. However, a comprehensive evaluation of its performance in antibiotic degradation has been lacking. To tackle this challenge, this study evaluates the effectiveness of this microwave plasma jet in degrading two widely used antibiotics, sulfamethoxazole and oxytetracycline, as well as their combined mixture. The results show that the proposed technology achieves excellent degradation and mineralization efficiencies. The removal rates for the mixed antibiotic solution are 11.13% and 26.28% higher than those for sulfamethoxazole and oxytetracycline individually. In order to optimize the experimental design, explainable artificial intelligence models were developed to predict degradation efficiency and identify key influencing factors. The computational models demonstrated high predictive accuracy, with Pearson correlation coefficients ranging from 0.978 to 0.991 when validated on independent datasets. Furthermore, free radical capture experiments revealed the critical role of hydroxyl radicals in the degradation process. Bio-toxicity assessments confirmed the ecological safety of the microwave plasma treatment. Finally, the analysis of reaction intermediates proposed potential degradation pathways, providing a molecular-level understanding of the degradation process. In conclusion, this study highlights the three-layer coaxial low-temperature atmospheric pressure microwave plasma as a highly effective technology for antibiotic removal and offers valuable insights for its application in wastewater treatment.