Treatment of TMP with α-MnO2/CA film coupled with dielectric barrier discharge system: Mechanism and safety assessment

The ecological risks from antibiotic residues in water require advanced treatment methods that ensure not just degradation but also complete detoxification. This study develops a highly efficient system coupling dielectric barrier discharge (DBD) plasma reactor with an α-MnO 2 /cellulose acetate (CA) catalytic membrane for the removal and detoxification of trimethoprim (TMP). The catalytic efficiency of the α-MnO 2 /CA films was assessed through comparative experiments within the DBD system, both with and without the films. Key performance indicators included the degradation kinetics of trimethoprim (TMP) in synthetic wastewater, energy efficiency, and reduction rates of total organic carbon (TOC) and chemical oxygen demand (COD). Using response surface methodology (RSM), the optimal conditions for degrading 20 mg/l of TMP were identified as 171.4W, 160 Hz, 5% catalyst loading, and a flow rate of 1200 ml/min, achieving a removal efficiency of 95.48% in 30 min. Variations in solution pH and the concentrations of H 2 O 2 and O 3 were monitored to confirm the catalytic function of α-MnO 2 /CA films. Additionally, quenching experiments demonstrated that free radicals contribute to degradation efficiency, ranking 1 O 2 > · O 2 − > · OH. A comprehensive toxicity assessment combining ECOSAR predictions and in vivo zebrafish embryo tests, confirmed the complete detoxification of the effluent, removal of neurobehavioral toxicity, and oxidative stress. Most importantly, restoring dihydrofolate reductase (DHFR) activity offered direct molecular-level proof that TMP's natural bioactivity was eliminated. This highlights that the DBD-α-MnO 2 /CA system exhibits lower toxicity and minimal bioaccumulation potential, positioning it as an environmentally safe and promising alternative to conventional methods for sustainable, large-scale applications. • Deep mechanistic understanding of the plasma-catalysis process. • DBD-α-MnO2/CA system showed pronounced synergistic effect. • Multi-level toxicological assessment confirmed complete detoxification of TMP. • Suggests long-term catalyst stability and treating complex real-world wastewater matrices.