Post-discharge treatment of air effluents polluted by butyl-mercaptan: the role of nitrate radical

Yn Liu (1) , L Braci (2) , S Cavadias (2) , S Ognier (2)

1 School of Environmental Science and Engineering
2 UPMC - Université Pierre et Marie Curie - Paris 6

Dry air polluted by butyl-mercaptan was treated in a Dielectric Barrier Discharge (DBD) reactor at atmospheric pressure using air as plasmagene gas in discharge and postdischarge modes. The energy density was varied between 200 to 1300 J/L. To assess the treatment efficiency, the concentrations of buty-mercaptan, total Volatile Organic Compounds (VOCs) and SO 2 were determined in the exhaust gas. Whatever the energy density was, the treatment efficiency was better in post-discharge mode. The butyl-mercaptan could be completely eliminated from 400 J/L and SO 2 selectivity was always low, below 10%. Measurements of CO, CO 2 and total VOCs indicated that 50 to 70% of the reaction products were condensed on the reactor wall in the form of micro-droplets, depending on the energy density. FTIR and XPS techniques were used to characterize the reaction products which were soluble in water. These analyses indicated that the reaction products contain oxygen, nitrogen and sulphur in an oxidized form. A reaction mechanism involving hydrogen abstraction from the -SH bond by the nitrate radical was proposed, pointing out the important role of nitrate radicals NO 3 in the reactivity of air flowing post-discharge.

Mots clés: Physical Sciences

Yn Liu, L Braci, S Cavadias, S Ognier. Post-discharge treatment of air effluents polluted by butyl-mercaptan: the role of nitrate radical. Journal of Physics D: Applied Physics, 2011, 44 (9), pp.95202. ⟨10.1088/0022-3727/44/9/095202⟩. ⟨hal-00599243⟩