Highly active Mn-Cu bimetallic oxide catalyst assembled as 3D-printed monolithic agitating paddles for advanced oxidation process

Abstract

Catalytically agitating paddles are essential to perform liquid-solid heterogeneous catalytic reactions on an industrial scale due to the improved mass transfer and easy catalyst recovery. Herein, bimetallic oxides were formed after the calcination of nanomaterials derived from metal-organic frameworks (MOFs). Particularly, Mn(M)-BTC nanomaterials were synthesized by self-assembly of Mn2+ ions (mixed with various dopants such as Cu2+, Ce3+, or Fe2+) and H3BTC ligands in a mixed solvent of ethanol and water. It was found that in the powdery form, the Mn-Cu oxide derivate exhibited the highest degradation rate in the catalytic wet peroxide oxidation process (CWPO process), which was significantly higher than that of single metal oxide as well as Mn-Fe and Mn-Ce oxide derivates. The reason was caused by the synergistic effect between Mn-Cu promoted the formation of Mn3+ and Cu+ species to boost the CWPO reaction. Furthermore, the obtained Mn-Cu powdery catalysts were 3D-printed to obtain monolithic agitating paddles with different geometries, which were then mounted on a central shaft in the stirred reactor. An advanced oxidation process was used to investigate the effect of 3D patterns on the degradation efficiency of various organic dyes. It was discovered that the 3D-printed grid with higher cell density (484 cpsi) had better liquid mixing efficiency and thus better catalytic performance, which could be repeatedly used more than seven times. Additionally, the numerical simulation analysis (computational fluid dynamics) revealed a good mixing efficiency and improved mass transfer in the entire reactor equipped with the designed monolithic agitating impellers.