Chinese Journal of Catalysis ›› 2019, Vol. 40 ›› Issue (5): 681-690.DOI: 10.1016/S1872-2067(18)63185-7

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Synergetic effect between non-thermal plasma and photocatalytic oxidation on the degradation of gas-phase toluene: Role of ozone

Haoling Yea,b, Yiqiu Liua,b, Si Chena,b, Haiqiang Wanga,b, Zhen Liuc, Zhongbiao Wua,b   

  1. a Key Laboratory of Environment Remediation and Ecological Health of Ministry of Education, College of Environmental & Resources Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China;
    b Zhejiang Provincial Engineering Research Center of Industrial Boiler & Furnace Flue Gas Pollution Control, Hangzhou 310027, Zhejiang, China;
    c Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310007, Zhejiang, China
  • Received:2018-08-29 Revised:2018-10-08 Online:2019-05-18 Published:2019-03-30
  • Contact: 10.1016/S1872-2067(18)63185-7
  • Supported by:

    This work was supported by the National Key Research and Development Plan of China (2016YFC0204700), National Natural Science Foundation of China (NSFC-51578488), Zhejiang Provincial "151" Talents Program (2013), Key Project of Zhejiang Provincial Science and Technology Program, the Program for Zhejiang Leading Team of S&T Innovation (2013TD07), and the Changjiang Scholar Incentive Program (2009).

Abstract:

In this study, a hybrid process using non-thermal plasma (NTP) and photocatalytic oxidation (PCO) was adopted for the degradation of gas-phase toluene using TiO2 as the photocatalyst. To discover the synergetic effect between NTP and PCO, the performances of both sole (O3, UV, NTP, and PCO) and combined (O3 + TiO2, O3 + UV, NTP + UV, O3 + PCO, and NTP + PCO) processes were investigated from different perspectives, such as the toluene removal efficiency, selectivity of COx, mineralization rate, ozone utilization, and the generation of by-products. The toluene removal efficiency of the combined NTP + PCO process was 80.2%, which was much higher than that of a sole degradation process such as NTP (18.8%) and PCO (13.4%). The selectivity of CO2 and the ozone utilization efficiency also significantly improved. The amount of by-products in the gas phase and the carbon-based intermediates adsorbed on the catalyst surface dramatically reduced. The improvement in the overall performances of the combined NTP + PCO process was mainly ascribed to the efficient utilization of ozone in the photocatalytic oxidation, and the ozone further acting as an electron acceptor and scavenger, generating more hydroxyl radicals and reducing the recombination of electron-hole pairs.

Key words: Non-thermal plasma, Photocatalytic oxidation, Synergetic effect, Ozone, Toluene