Synergistic Degradation Performance And Mechanism Of 17β-Estradiol By Dielectric Barrier Discharge Non-Thermal Plasma Combined With Pt-TiO₂

17β-Estradiol (E2) as a common natural estrogen, mainly concerned principal, natural and most potent oestrogen, is ubiquitous in the aquatic environment systems. Therefore, the development of an effective process for removing E2 from water and wastewater has important significance. A synergistic system of dielectric barrier discharge non-thermal plasma (DBDow) combined with Pt-TiO2 photocatalyst has been developed to investigate the degradation of E2. The effect of four parameters on E2 removal efficiencyand kinetics rate constant were investigated, that were peak voltage, initial E2 concentration, initial pH value, and Pt-TiO2 additive amount. In addition, possible degradation pathways of E2 were proposed based on the analytical results of UPLC-QTOF-MS. The main research results are as follows.(1) After a 30 min reaction,94% of E2 was removed and 439.4 X 10-6g/kW·h was obtained in coulping system with addition of TiO2, while only 72% and 329.2 X 10-6g/kW·h in simple DBDow system, indicating that the TiO2 photocatalyst diffused in solution played a great role in photocatalytic degradation of E2. In DBDow coulping with Pt-TiO2 system, the removal efficiency and energy utilization efficiency were further increased, reaching 98% and 468.1 × 10-6g/kW·h, respectively, indicating that the doping of Pt had a positive effect on the degradation of E2.(2) The degradation kinetics of E2 followed first-order kinetics model during the DBDowcoulping with Pt-TiO2 system. The maximum reaction rate constant (k 0.2227 min-1) was achieved at E2 concentration of 400 μg/L with a peak voltage 12 kV and Pt-TiO2 additive amount 50 mg/L.(3) A total of 6 by-products were identified by ultra-performance liquid chromatography coupled to quadrupole-time of flight tandem mass spectrometry (UPLC-QTOF-MS) techniques, and a tentative reaction scheme was proposed. The degradation mechanisms revealed that the active species of hydroxyl radicals, ozone and hole (h+) play a key role for degradation E2 in the synergistic system.