In this study, mixed oxides of Mn-Cu and Fe-Cu on OMS-2 support having an octahedral structure were synthesized by the refluxing and impregnation methods. The characteristics of the materials were analyzed by XRD, FTIR, SEM, EDX, and H2-TPR. In the CO oxidation test, CuFeOx/OMS-2 had slightly higher catalytic activity but is significantly more stable than CuMnOx/OMS-2 and CuO/OMS-2. Due to its lower reduction temperature in H2-TPR analysis, the Mars-Van-Krevelen mechanism for CuFeOx/OMS-2 (Cu2+–O–Fe3+ ↔ Cu+–□–Fe2+) could take place more energetically than CuO/OMS-2 and CuMnOx/OMS-2 (Cu2+–O2−–Mn4+ ↔ Cu+–□–Mn3+). In addition, the interaction between Fe and Cu in the catalyst could improve the durability of the surface oxides structure in comparison with that between Mn and Cu. With the high specific rate and TOF of 28.6 mmol/h.g and 0.508, respectively, CuFeOx/OMS-2 has a great potential as an effective catalyst for low-temperature oxidation application in CO and possible VOCs removal.

Carbon monoxide (CO) is a very toxic pollutant emitted from wood fired boiler, which is widely used in small and medium enterprises in Vietnam. The treatment of CO containing flue gas faces many difficulties due to the inert property of CO and cannot be removed by traditional adsorption and absorption methods and one of the effective CO treatments is catalytic oxidation. Therefore, we aimed to prepare various catalysts on different carriers for treatment of CO in flue gas, including γ-Al2O3-based metal oxides (Co3O4/Al2O3, Cr2O3/Al2O3, and CuO/Al2O3), CuO–MnOx/OMS-2, and CuO-MnOx/zeolite. The CO removal tests were conducted in a continuous fixed bed reactor in laboratory scale with temperature range of 50 – 550 oC. The characteristics of catalytic materials were then determined by various methods such as Brunauer-Emmett-Teller measurement, X-ray diffraction, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. Results showed that CuO-MnOx/OMS-2 was the best catalyst with high removal efficiency of 98.41% at reactor temperature of 250 oC while gas outlet temperature of < 50 oC, proving the suitability of this material for practical treatment of CO in flue gas. The reaction follows Mars-Van-Krevelen mechanism with the presence of Cu2+-O2--Mn4+ ↔ Cu+-o-Mn3+ + O2 redox in the structure of the material. Moreover, the effect of environmental factors such as flow rate, inlet CO concentration, and catalysts amount on the CO removal efficiency were investigated and noted for designing and operation purposes. Concentration of outlet CO met well QCVN 19: 2009/BTNMT - National technical regulation on industrial emissions for dust and inorganic substances. Therefore, CuO-MnOx/OMS-2 catalyst material could be a potential catalyst for treatment of CO in flue gas of boiler.