Products, reactive species and mechanisms of PFOA degradation in a self-pulsing discharge (SPD) plasma reactor

• DOI: 10.1016/j.chemosphere.2023.139972
• Publication Date: 2023-08-26T03:23:40Z
• Authors: Omar Biondo; Giulia Tomei; Mubbshir Saleem; Goran B. Sretenović; Mirko Magarotto; Ester Marotta; Cristina Paradisi
• Keywords: Degradation

Non-thermal plasma is a promising tool for novel technologies to treat water contaminated by recalcitrant pollutants. We report here on products, reactive species and mechanisms of the efficient degradation perfluorooctanoic acid (PFOA) achieved with self-pulsing discharge developed previously in our lab. Air or argon were used as feed gas, ultrapure tap aqueous medium. Identified organic intermediate products arise from chain-shortening defluorination reactions, latter achieving not only C-F C-H exchange (hydro-de-fluorination), reported literature, but also C-OH (hydroxy-de-fluorination). In contrast chain-shortening, yielding lower homologues PFOA via selective cleavage C-C bond at carboxylate group, occurs various sites alkyl chain giving mixtures different isomeric products. Plasma generated investigated under all experimental conditions tested, using specific chemical probes optical emission spectroscopy. Cross-analysis results revealed striking direct correlation energy efficiency production electrons. contrast, no was observed bands either Ar+ OH radical. These indicate prevalent role electrons initiating above liquid.