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Preparation and testing of cordierite monolithic catalysts for oxidation of aromatic volatile organic compounds

Air pollution is a problem that is attracting more and more attention and is at the center of numerous researches. Rapid industrialization and global development result in an increase in pollution, and volatile organic compounds are an example of large group of pollutants that are dangerous to human health and environment. Catalytic oxidation proved to be a promising process for the degradation of volatile organic compounds and one of the most efficient and economically acceptable processes for their decomposition. Catalysts for this application are generally divided into noble metals and metal oxides. Although noble metals, such as palladium and platinum, are more catalytically active than transition metal oxides, their use is limited due to their high cost and susceptibility to poisoning by chlorinated and sulphuric compounds that can be present in the polluted gas. The aim of this work is to develop monolithic catalysts for catalytic oxidation of aromatic volatile organic compounds. A gaseous mixture of benzene, toluene, ethylbenzene and o-xylene (BTEX) in nitrogen was used as a model component. Reactions were carried out in a monolithic reactor at different temperatures, with a constant initial concentration of reactants (BTEX) and a constant ratio of reactant and oxidant (synthetic air). Gaseous mixtures were analyzed on-line before and after reaction using gas chromatography. The work involves finding the optimal chemical composition of the catalytic layer on inert cordierite carrier, using different combinations of transition metals oxides (manganese with copper, iron and nickel) and palladium as a representative of noble metals. The prepared cordierite monolithic catalysts showed acceptable mechanical stability and high performance regarding oxidation of the mixture of aromatic compounds. High conversion values (>95 %) of all components of the mixture was achieved at a temperature around 200 ⁰C, depending on the chemical composition of the catalytic layer. A comparison with the activity of a commercial monolithic catalyst (Purelyst PH-304) was also performed and appropriate conclusions were drawn.

catalytic oxidation ; monolithic catalysts ; volatile organic compounds, manganese oxides

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