Effect of gas composition on pulsed corona discharge characteristics and Hg ⁰ removal performance

Abstract Plasma technology effectively removes Hg 0 by oxidizing it via highly reactive species, offering an efficient and rapid approach for mercury emission control. In this work, we investigated the mechanism of Hg 0 (g) removal by pulsed corona discharge non-thermal plasma in pure N 2 and N 2 (80%)-O 2 (20%) mixtures (or simulated air). Experimental and simulation methods were employed to thoroughly investigate corona discharge electrical characteristics, optical properties, and Hg 0 removal efficiency, while plasma processes and particle evolution mechanisms were analyzed. Hg 0 was effectively removed in pure N 2 under pulsed corona discharge, achieving 79% efficiency. Despite discharge instability in simulated air due to oxygen’s electronegativity, its strong oxidizing ability enabled nearly complete Hg 0 oxidation via enhanced plasma chemistry. Mechanistic analysis indicates that the pulse corona discharge generates abundant high-energy electrons and reactive oxygen species, which play a critical role in the effective removal of Hg 0 . The reactive oxygen species in the N 2 -O 2 plasma is suggested to be the key issue for improving the efficiency of Hg 0 removal. The higher electron temperature in simulated air helps provide sufficient reactive conditions for Hg 0 removal. This research provides valuable insights into the development of more effective non-thermal plasma systems for Hg 0 control and enhances the theoretical foundation of plasma technology for Hg 0 removal.