Degradation mechanisms of organic compounds in molten hydroxide salts: a radical reaction yielding H and graphite.
Florent Lecomte, Ana Gabriela Porras Guiterrez, Marielle Huvé, Alain Moissette, Giuseppe Sicoli, Anne-Laure Rollet, Sylvie Daviero-Minaud
Author Information
Florent Lecomte: Unité de Catalyse et Chimie du Solide (UCCS), Université de Lille 59655 Villeneuve d'Ascq France sylvie.daviero@univ-lille.fr.
Ana Gabriela Porras Guiterrez: Laboratoire Physico-Chimie des Electrolytes et Nanosystèmes Interfaciaux (PHENIX), CNRS, Sorbonne Université 75005 Paris France anne-laure.rollet@sorbonne-universite.fr. ORCID
Marielle Huvé: Unité de Catalyse et Chimie du Solide (UCCS), Université de Lille 59655 Villeneuve d'Ascq France sylvie.daviero@univ-lille.fr.
Alain Moissette: Laboratoire de Spectrochimie pour l'Interactions, la Réactivité et l'Environnement (LASIRE), Université de Lille 59655 Villeneuve-d'Ascq France. ORCID
Giuseppe Sicoli: Laboratoire de Spectrochimie pour l'Interactions, la Réactivité et l'Environnement (LASIRE), Université de Lille 59655 Villeneuve-d'Ascq France.
Anne-Laure Rollet: Laboratoire Physico-Chimie des Electrolytes et Nanosystèmes Interfaciaux (PHENIX), CNRS, Sorbonne Université 75005 Paris France anne-laure.rollet@sorbonne-universite.fr.
Sylvie Daviero-Minaud: Unité de Catalyse et Chimie du Solide (UCCS), Université de Lille 59655 Villeneuve d'Ascq France sylvie.daviero@univ-lille.fr. ORCID
Molten salts are used in various waste treatments, such as recycling, recovery or making inert. Here, we present a study of the degradation mechanisms of organic compounds in molten hydroxide salts. Molten salt oxidation (MSO) using carbonates, hydroxides and chlorides is known for the treatment of hazardous waste, organic material or metal recovery. This process is described as an oxidation reaction due to the consumption of O and formation of HO and CO. We have treated various organic products, carboxylic acids, polyethylene and neoprene with molten hydroxides at 400 °C. However, the reaction products obtained in these salts, especially carbon graphite and H without CO emission, challenges the previous mechanisms described for the MSO process. Combining several analyses of the solid residues and the gas produced during the reaction of organic compounds in molten hydroxides (NaOH-KOH), we demonstrate that these mechanisms are radical-based instead of oxidative. We also show that the obtained end products are highly recoverable graphite and H, which opens a new way of recycling plastic residues.
