| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for effectively making a nitrogen oxide harmless by NH<SB>3</SB>at a low temperature using a low-cost zeolite catalyst without supporting an active metal and NH<SB>3</SB>. <P>SOLUTION: The catalyst, which consists of a hydrogen-type and/or ammonium-type β-zeolite without having a catalytically-active metallic species supported, is made to contact a treatment gas containing NO and NO<SB>2</SB>while adding NH<SB>3</SB>as a reduction component. It is preferable that the mol ratio of silica(SiO<SB>2</SB>) to alumina(Al<SB>2</SB>O<SB>3</SB>) in the β-zeolite is 20-200, the content of NO<SB>2</SB>in the treatment gas is in the range of 0.5-1.5 by the mol ratio to NO, and the treatment temperature is 150°C or above. <P>COPYRIGHT: (C)2007,JPO&INPIT |
