RESUMEN

Two mesoporous silica materials, MSU-H and mesoporous SAPO-34 (Meso-SAPO-34), were applied to the catalytic oxidation with ozone of benzene. The catalysts were characterized by X-ray diffraction, N2 adsorption-desorption, Brunauer-Emmett-Teller specific surface area, and H2-temperature programmed reduction. When MnO(x)/MSU-H was used at three different temperature, 50 degrees C, 80 degrees C, and 100 degrees C, the ozone conversion and CO(x) yield increased with increasing temperature. MnO(x)/MSU-H exhibited much higher catalytic activity than that of MnO(x)/Meso-SAPO-34. The high catalytic activity of MnO(x)/MSU-H seems to be due to the high oxygen ability and structural stability of MSU-H. The CO2 yield was somewhat enhanced by the addition of steam because steam facilitated desorption of the reaction intermediates adsorbed on the catalyst surface, enabling them to be oxidized further.

RESUMEN

The catalytic oxidation of benzene was carried out over mesoporous alpha-Mn2O3, MnOx/KIT-6, and bulk commercial Mn oxides (Mn2O3, MnO2, and MnO). The catalysts were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller analysis, and temperature-programmed reduction analysis. MnOx/KIT-6, prepared by impregnating MnOx on KIT-6, exhibited a low activity for the oxidation of benzene, whereas mesoporous alpha-Mn2O3, manufactured using KIT-6 as the template, showed a high activity. The order of the activities of bulk Mn oxides for benzene decomposition was shown to be Mn2O3 > MnO2 > MnO. Therefore, the high activity of mesoporous alpha-Mn2O3 is attributed to the uniform distribution of highly active Mn2O3 in the mesoporous structure.

Asunto(s)

Benceno/química , Compuestos de Manganeso/química , Nanoestructuras/química , Nanoestructuras/ultraestructura , Óxidos/química , Catálisis , Ensayo de Materiales , Oxidación-Reducción , Tamaño de la Partícula , Porosidad

RESUMEN

The removal of formaldehyde at low concentrations is important in indoor air pollution research. In this study, mesoporous carbon with a large specific surface area was used for the adsorption of low-concentration indoor formaldehyde. A mesoporous carbon material, CMK-3, was synthesized using the nano-replication method. SBA-15 was used as a mesoporous template. The surface of CMK-3 was activated using a 2N H2SO4 solution and NH3 gas to prepare CMK-3-H2SO4 and CMK-3-NH3, respectively. The activated samples were characterized by N2 adsorption-desorption, X-ray diffraction, and X-ray photoelectron spectroscopy. The formaldehyde adsorption performance of the mesoporous carbons was in the order of CMK-3-NH3 > CMK-3-H2SO4 > CMK-3. The difference in the adsorption performance was explained by oxygen and nitrogen functional groups formed during the activation process and by the specific surface area and pore structure of mesoporous carbon.