engleski

Investigation of the potential of stereolithography as a possible method for the production of ceramic monolithic catalysts

In chemical engineering, the term monolith refers to structures with clearly defined and invariable geometry. They are usually produced by extrusion (ceramic monoliths, usually made of synthetic cordierite) or by coiling and grooving (metal monoliths, usually made of stainless steel). In recent years, the possibility of 3D printing, i.e. additive manufacturing (AM), has been explored for various applications in the field of biotechnology and chemical sciences, but also in the field of catalytic reaction engineering as an advanced method to fabricate complex monolithic catalysts/reactors from different materials. In this work, stereolithography (SLA) was used to fabricate ceramic monolithic catalyst carriers for the preparation of potential monolithic catalysts for the catalytic oxidation of a benzene/toluene/ethylbenzene/o-xylene (BTEX) gaseous mixture. This approach involves the preparation of inert catalyst carriers, on the surface of which the catalytically active components are subsequently deposited using the impregnation technique. The prepared monolithic catalysts differed in the characteristic geometry of the channels, resulting in different geometric surface areas (11 cm2, 15 cm2, 20 cm2, and 22 cm2) of the monolithic catalysts. As catalyst precursors, 1 M aqueous solutions of manganese(II) nitrate tetrahydrate, copper(II) nitrate trihydrate, iron(III) nitrate nonahydrate, and nickel(II) nitrate hexahydrate were used. Two-component mixed oxides of manganese and transition metals (Fe, Cu and Ni) were used as catalytically active components. As expected, the conversion of the BTEX components increased with increasing temperature, and characteristic S-shaped curves (i.e., self-ignition curves) were obtained. The carrier with a geometric surface area of 22 cm2 proved to be the best, as expected, while in terms of the chemical composition of the catalyst, the best results were obtained with MnFeOx, followed by MnCuOx with very similar conversion values, and MnNiOx, which proved to be less catalytically active under the tested operating conditions.

Stereolithography ; Monolithic catalysts ; Impregnation ; Mixed manganese oxides ; Catalytic oxidation

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