Degradation of herbicides in water using non-thermal plasmas (NTP) at atmospheric pressure

The intensive use of pesticides in agriculture leads to the contamination of surface water and groundwater. These persistent organic pollutants (POPs) exhibit inherent toxicity, posing environmental and health risks due to their stable molecular structures and potential to form hazardous by-products. However, conventional methods used in wastewater treatment plants remain partially effective for these pollutants. Advanced oxidation processes are introduced to degrade these toxic molecules [1]. Among the advanced oxidation processes (AOP), the use of plasma has already proven its potential todegrade persistent organic pollutants [2, 3]. Thus, this research focuses on the degradation by non-thermal plasma (NTP) processes at atmospheric pressure of the herbicides present in the water. The main goal of the first part of this study is to perform a comparative analysis of the efficiency ofthree plasma reactors at atmospheric pressure (Glidarc, DBD and plasma jet) in terms of the production of key reactive species, such as hydrogen peroxide or acids/bases derived from nitrogen generated in Plasma Activated Distilled Water (PADW). Chemical analysis (spectrophotometry/UV-visible colorimetry) is performed. Furthermore, the energy efficiency of each plasma reactor is characterized. The second part of this work is dedicated to testing the capacity of the chosen plasma reactor to treat a target herbicide. Acknowledgement: The authors are grateful to François Faubert for his guidance and experience with the Gas chromatography-mass spectrometry technique.[1] F. Zaviska, P. Drogui, G. Mercier, and J. Blais, Procédés d’oxydation avancée dans le traitement des eauxet des effluents industriels : Application à la dégradation des polluants réfractaires. Rev. Des Sci. DeL’Eau 22(4), 535–564, (2009).[2] P. Vanraes, N. Wardenier, P. Surmont, F. Lynen, A. Nikiforov, S.W.H. Van Hulle, C. Leys, A. Bogaerts,Removal of alachlor, diuron and isoproturon in water in a falling film dielectric barrier discharge (Dbd) reactorcombined with adsorption on activated carbon textile: Reaction mechanisms and oxidation by-products. J.Hazard. Mater. 354, 180-190, (2018).[3] M. Magureanu, N.B. Mandache, V.I. Parvulescu, Degradation of pharmaceutical compounds in water bynon-thermal plasma treatment. Water Research 81, 124-136, (2015).