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Plasma Sci. Technol. ›› 2018, Vol. 20 ›› Issue (5): 054009.doi: 10.1088/2058-6272/aaab42

• THE 8TH INTERNATIONAL CONFERENCE ON APPLIED ELECTROSTATICS • Previous Articles     Next Articles

A comparative study on the activity of TiO2 in pulsed plasma under different discharge conditions

Lijuan DUAN (段丽娟)1,2, Nan JIANG (姜楠)2,3, Na LU (鲁娜)2,3 , Kefeng SHANG (商克峰)2,3, Jie LI (李杰)2,3 and Yan WU (吴彦)2,3   

  

  1. 1 School of Environmental Science & Technology, Dalian University of Technology, Dalian 116024, People’s Republic of China 2 Key Laboratory of Industrial Ecology and Environmental Engineering, MOE, Dalian University of Technology, Dalian 116024, People’s Republic of China 3 School of Electrical Engineering, Dalian University of Technology, Dalian 116024, People’s Republic of China
  • Received:2017-11-23 Published:2018-01-25
  • Supported by:

    The authors thank the projects funded by the Fundamental Research Funds for the Central Universities under Grant (DUT 15QY17) and National Natural Science Foundation of China (Project Nos. 51477025 and U1462105) for their financial support to this research.

Abstract:

In the present study, a combination of pulsed discharge plasma and TiO2 (plasma/TiO2) has been developed in order to study the activity of TiO2 by varying the discharge conditions of pulsed voltage, discharge mode, air flow rate and solution conductivity. Phenol was used as the chemical probe to characterize the activity of TiO2 in a pulsed discharge system. The experimental results showed that the phenol removal efficiency could be improved by about 10% by increasing the applied voltage. The phenol removal efficiency for three discharge modes in the plasma-discharge-alone system was found to be highest in the spark mode, followed by the spark–streamer mode and finally the streamer mode. In the plasma/TiO2 system, the highest catalytic effect of TiO2 was observed in the spark–streamer discharge mode, which may be attributed to the favorable chemical and physical effects from the spark–streamer discharge mode, such as ultraviolet light, O3,H2O2, pyrolysis, shockwaves and high-energy electrons. Meanwhile, the optimal flow rate and conductivity were 0.05 m3 l-1 and 10 μS cm-1, respectively. The main phenolic intermediates were hydroquinone, catechol, and p-benzoquinone during the discharge treatment process. A different phenol degradation pathway was observed in the plasma/TiO2 system as compared to plasma alone. Analysis of the reaction intermediates demonstrated that p-benzoquinone reduction was selectively catalyzed on the TiO2 surface. The effective decomposition of phenol constant (De) increased from 74.11% to 79.16% when TiO2 was added, indicating that higher phenol mineralization was achieved in the plasma/TiO2 system.

Key words: pulsed discharge plasma, TiO2, phenol degradation, discharge conditions