Improving the Activity of Rh/Al2O3 Catalyst for NO Reduction by Na Addition in the Presences of H2O and O2

Abstract

The effect of Na addition on the performance of Rh/Al 2 O 3 catalyst for NO reduction with CO in the presence of H 2 O and O 2 was investigated. The reacted catalysts were analyzed by the FTIR technique to identify the products for further investigation on the possible catalytic reaction mechanisms and the reasons behind the H 2 O poisoning. Experimental results show that the removal efficiency of NO by Rh/Al 2 O 3 catalyst was 63% at 250°C but that decreased as the H 2 O content increased. Adding Na to modify the Rh/Al 2 O 3 catalyst significantly enhanced the conversion of NO to 99% at 250-300°C even as the H 2 O content was 1.6 vol%. The FTIR analyses results reveal that the abundant H 2 O in the flue gas can compete with NO to adsorb on the surfaces of Rh/Al 2 O 3 and Rh-Na/ Al 2 O 3 catalysts and further enhance the formation of NO 3 that reacts with H. The effects of H 2 O on Rh/Al 2 O 3 and Rh-Na/Al 2 O 3 catalysts can be eliminated by increasing the reaction temperature to higher than 300°C. Rh-Na/Al 2 O 3 is a feasible catalyst for NO reduction at such condition with relative high H 2 O and O 2 contents.

Optimization of Heterogeneous Photosensitized Oxidation for Winery Effluent Treatment

“…This may be associated with the fact that the catalysts' active sites were occupied by the photosensitizer; therefore, there were no sites available to adsorb the contaminants present in winery wastewater. This agrees with the study of Chang et al [38], where the active sites of the catalyst were occupied with H 2 O, which led to a decrease in efficiency, since the pollutant was not absorbed as the H 2 O blocked the active sites.…”