Co–Mg–Al oxides issued of hydrotalcite precursors for total oxidation of volatile organic compounds. Identification and toxicological impact of the by-products

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• 作者：Cé ; dric Gennequin ; Serge Kouassi ; Lucette Tidahy ; Renaud Cousin ; Jean-Franç ; ois Lamonier ; Guillaume Garcon ; Pirouz Shirali ; Fabrice Cazier ; Antoine Aboukaï ; s ; Sté ; phane Siffert
• 关键词：VOC ; Catalytic oxidation ; Co-Mg-Al catalysts ; Hydrotalcite ; Lung toxicity ; L132 cells ; Toluene ; Benzene ; Cytotoxicity tests
• 刊名：Comptes Rendus Chimie
• 出版年：2010
• 出版时间：May 2010
• 年：2010
• 卷：13
• 期：5
• 页码：494-501
• 全文大小：703 K

文摘

Catalysts based on Co-Mg-Al, which were used for the total oxidation of toluene, were synthesized by using the hydrotalcite pathway. The calcination allowed us to obtain various mixed oxide types (i.e. Co₃O₄, Co₂AlO₄ or CoAl₂O₄), presenting mesopores of about 8 nm and high specific surface areas. The solids were tested for the total oxidation of toluene and showed a total selectivity in CO₂ and H₂O for 100 % of toluene conversion. However, studies using diffuse reflectance infrared “operando” and GC-MS allowed us to identify intermediary by-products stemming from the catalytic oxidation of toluene: benzene and small quantities of benzaldehyde, styrene and acetophenone. In order to contribute to the improvement of the current scientific knowledge on volatile organic compound (VOC) toxicity in humans, the lung toxicity of toluene, benzene or their association was determined by using a human epithelial lung cell model (i.e. L132 cell line). VOC cytotoxicity was studied with three complementary methods: the enzymatic activity of extracellular lactate dehydrogenase (LDH), the enzymatic activity of mitochondrial dehydrogenase (mDH), and the incorporation of 5-Bromodesoxyuridine (5-BrdU). Taken together, these results showed the occurrence of adverse effects, notably reported by significant increases in LDH activity in cell culture supernatants, 24 hours after L132 cell exposure not only to toluene alone or benzene alone, but also to their association. This original approach allowed us to integrate some toxicological parameters to help the choice of new-dedicated catalysts for the oxidative conversion of VOC.