Effects of the N-2 to O-2 ratio in air on the removal rate and the degree of decomposition of 2-chloroethyl ethyl sulphide by atmospheric plasma

It is difficult to simultaneously satisfy all the essential requirements for the removal of chemical warfare agents from air through atmospheric air plasma chemistry. Such requirements include a high removal rate (RR) indicating the completeness of the transition into other substances and a high degree of decomposition (DD) indicating the toxicity of these substances. In this study, the N-2 to O-2 ratio (NOR) in air was adjusted to scrutinise the role of electrons and active oxidative particles in 2-chloroethyl ethyl sulphide removal. It was found that a high NOR led to a high RR, but a low DD. Spectral diagnosis was used to compare the electron temperature (T-e) of the plasma at different NORs. Plasma kinetics based on the calculation of the electron Boltzmann equation and product analysis were conducted. The results showed that the T-e increased with increasing NORs, while the production rate of active oxidative particles tended to decrease at higher NORs. Thus, this study suggests that high-energy electrons may dominate the RR, while active oxidative particles may play a dominant role in enhancing the DD. The results may lead to a novel methodology that modifies the NORs to achieve both optimum RR and DD.