This study investigated the degradation feasibility of N, N-diethyl-m-toluamide (DEET) in aqueous solution by water falling film dielectric barrier discharge (DBD) plasma under three different operating modes. The results exhibited that bubbling the gas of discharge area into DEET solution at the same time of DEET solution flowing through the discharge area (model-3) achieved better effect, the degradation efficiency and rate constant of 300 mL DEET solution with initial concentration of 20 mg/L could reach 76.8% and 0.0526 min −1 , respectively, after 27 min. In addition, the energy yield of model-3 was highest. The reactive species (H 2 O 2 , O 3 ) generated from the DBD system were measured, and the effects of different radical scavengers were analysed. Meanwhile, the removal efficiency of total organic carbon (TOC) in model-3 was much higher, could reach about 24%. The effects of various parameters such as discharge voltage, initial pH, gas bubbling flowrate and liquid circulation flowrate on the degradation of DEET in model-3 were further examined and it was also observed that higher discharge voltage, lower pH, larger gas bubbling flowrate and larger liquid circulation flowrate could promote the removal of DEET. Finally, the DEET degradation pathway was deduced based on HPLC-MS analysis and Gaussian calculation.
Zhen Li,Yawen Wang,He Guo,Shijia Pan,Chendong Puyang,Yingying Su,Weichuan Qiao,Jiangang Han
Development of efficient abatement technology for drugs and personal care products (PPCPs) has important scientific and practical significance to restrain its discharge to the natural water environment. This research aims to investigate ibuprofen (IBP) elimination in water film dielectric barrier discharge (DBD) plasma system driven by pulse power. With raising input power, the removal rate was improved. When input was 95 W, the removal rate and kinetic constant were up to 96.1% and 0.090 min −1 , respectively. Besides, heightening frequency, duty ratio and solution flowrate would promote the degradation of IBP. IBP were more favorably degraded at lower IBP concentration and neutral pH condition. Active species including ·OH, electron, 1 O 2 and · O 2 – dominated decomposition of IBP. The generation of O 3 , · OH and H 2 O 2 in deionized water and IBP solution was compared. UV–Vis spectrum and three dimensional fluorescence spectroscopy illustrated that IBP molecules could be decomposed effectively after DBD plasma treatment. During IBP degradation, COD and TOC was also relieved with extension of treatment time. The possible degradation routes of IBP in water film DBD plasma system were proposed based on LC-MS and Discrete Fourier transform (DFT) simulation. Based on the identified intermediates, their potential toxicity was evaluated with the help of US-EPA-TEST software. Water film DBD plasma technology was also suitable for actual wastewater treatment. The comparison of other technologies for IBP degradation was carried out finally. This work can provide exploratory platforms for comprehensively understanding and enhancing IBP degradation in DBD plasma technology.
危险品化学品经营许可证（带存储）