The CoAlCeO Mixed Oxide: An Alternative to Palladium-Based Catalysts for Total Oxidation of Industrial VOCs

Julien Brunet,Renaud Cousin,Fabrice Cazier,Guy De Weireld,Thierry Visart De Bocarmé,Eric Genty,Cédric Barroo,Diane Thomas,Stéphane Siffert,Christophe Poupin

doi:10.3390/catal8020064

Abstract

Catalytic total oxidation is an effective technique for the treatment of industrial VOCs principally resulting from industrial processes using solvents, and usually containing mono-aromatics (BTEX) and oxygenated compounds (acetone, ethanol, butanone). The catalytic total oxidation of VOCs on noble metal materials is effective. However, the cost of catalysts is a main obstacle for the industrial application of these VOC removal processes. Therefore, the aim of this work is to propose an alternative material to palladium-based catalysts (which are suitable for VOCs’ total oxidation): a mixed oxide synthesized in the hydrotalcite way, namely CoAlCeO. This material was compared to four catalytic materials containing palladium, selected according to the literature: Pd/α-Al2O3, Pd/HY, Pd/CeO2 and Pd/γAl2O3. These materials have been studied for the total oxidation of toluene, butanone, and VOCs mixtures. Catalysts’ performances were compared, taking into account the oxidation byproducts emitted from the process. This work highlight that the CoAlCeO catalyst presents better efficiency than Pd-based materials for the total oxidation of a VOCs mixture.

Highlights

Volatile organic compounds (VOCs) are known as one of the major contributors to atmospheric pollution
The results show that the mixed oxide has a lower performance than palladium-based catalysts
The results presented are discussed according to two aspects: (i) the light-off curves of VOCs alone and in mixture are compared to assess mixing effects between toluene and butanone for each catalyst; (ii) the light-off curves of the binary mixture are compared in order to differentiate the performance of each catalyst

Summary

Introduction

Volatile organic compounds (VOCs) are known as one of the major contributors to atmospheric pollution. Their anthropic release is significant in industrialized areas and has noxious consequences for health, environment, and construction materials. The majority of VOC emissions originates from solvents used in several industrial sectors (paints, varnishes, lacquers, inks, adhesives, glues, etc.). A significant part of these solvents is composed of mono-aromatic compounds, . The other part of these solvents is represented by oxygenated compounds, such as butanone (or methyl ethyl ketone (MEK)) which is a common oxygenated solvent, since it is a less toxic substitute for alcohols (methanol, ethanol) and acetone. Butanone and BTEX are widely used in mixtures as solvent for lacquers, inks, and coatings for application to metal surfaces

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Conclusion