Application of proton transfer reaction mass spectrometry for the assessment of toluene removal in a nonthermal plasma reactor

Abstract

Proton transfer reaction mass spectrometry (PTR-MS) is a mature technique for the real-time measurement and monitoring of volatile organic compounds in the atmosphere. In this paper, a modified quantification method for PTR-MS was used to assess the performance of nonthermal plasma (NTP) reactor for the removal of toluene which was widely used in industrial production processes. Toluene and 11 corresponding organic by-products were tentatively identified and quantified by a proton transfer reaction time-of-flight mass spectrometer. The degradation dynamics of toluene and the formation of organic by-products were monitored in real-time (resolution = 1 second) under "plasma off" and "plasma on" conditions. We conclude that initial concentration and gas flow rate were the key parameters in the health risk assessment of NTP for the removal of toluene. The toluene removal efficiency and CO selectivity decreased with increasing upstream toluene concentration or gas flow rate, whereas the health risk influence index increased with increasing upstream toluene concentration or gas flow rate. The highest removal efficiency of toluene (100%), CO selectivity (53.2%), and the best health risk influence index for organic by-products (0.11) were achieved when the toluene concentration was kept at 105 ppmv and flow rate at 0.4 L/minute. The results demonstrate that PTR-MS is a promising tool to improve the practical applications of volatile organic compound removal by NTP because it can be used to optimize the NTP working conditions by providing a precise, fast, and clear health risk assessment for organic by-products based on their real-time analysis.

Effect of the component and the concentration ratio on the removal of volatile organic compound mixtures by non-thermal plasma

“…The change in the discharge voltage was exactly the same for all three VOCs; however, the discharge current was slightly different, which resulted in the shift of the data points for the three curves along the horizontal axis. As shown in figure3(a), the degradation rate of these three VOCs increases proportionally with the increase in SIE, which is similar to the pattern reported in[46][47][48]. The degradation rate of TOL was significantly higher than that of EA and AC.…”

C-dot doping for enhanced catalytic performance of TiO2/5A for toluene degradation in non-thermal plasma-catalyst system

“…The structure of the DBD reactor that was introduced in our previous work (Guo et al 2018b) is shown in Fig. 2.…”

“…The plasma was generated by a high-voltage power supply (CTP-2000k, Nanjing Moersi Electronics Co., Ltd., China), and its electrical characterization was monitored by a digital storage oscilloscope (DSO7052A, Agilent, USA). The discharge power (p) is calculated by multiplying the area of the charge-voltage Lissajous figure S by the frequency f (Guo et al 2018b;Jiang et al 2013)…”

“…Very recently, NTP degradation of toluene (Guo et al 2018a, b) was investigated by our group in a DBD reactor. Toluene and its organic by-products were characterized and quantified in real time using a proton-transfer reaction timeof-flight mass spectrometry (PTR-TOF-MS) instrument with a modified quantification method (Guo et al 2018b). These studies enabled real-time online monitoring of organic reactant and product concentrations during NTP degradation.…”