Showing papers by "Masakazu Iwamoto published in 1989"
TL;DR: In this paper, repeated ion exchange of the ZSM-5 zeolite using aqueous copper(II) acetate solution was found to bring about excess loading of copper ions above 100% of exchange level.
Abstract: Repeated ion exchange of the ZSM-5 zeolite using aqueous copper(II) acetate solution was found to bring about excess loading of copper ions above 100% of exchange level. The catalytic activities of the resulting Cu-ZSM-5 zeolites for direct decomposition of nitrogen monoxide were very high and increased with increasing exchange level. The activity did not decrease even after 30 h of continuous service.
184 citations
TL;DR: In this paper, the catalytic activity of Y zeolites containing copper ions (CuY) for decomposition of nitrogen monoxide was enhanced through additional exchange of other metal ions or evacuation treatment around 923-973 K.
Abstract: Catalytic activity of Y zeolites containing copper ions (CuY) for decomposition of nitrogen monoxide was enhanced through additional exchange of other metal ions or evacuation treatment around 923–973 K. In the first case, Co3+ or Ni2+ ions increase the catalytic activity while Ca2+, Mn2+, Fe2+, and Zn2+ diminish the catalytic activity of CuY. In the second case, the catalytic activity of CuY evacuated at 973 K was twice that of CuY without the evacuation treatment, which is discussed in connection with the increment of Cu ions active for the decomposition.
59 citations
TL;DR: In this article, the catalytic decomposition of NO has been investigated over various copper ion-exchanged zeolites, and the number of Cu2+ ions available for NO adsorption is dependent on the zeolite structure.
Abstract: The catalytic decomposition of NO has been investigated over various copper ion-exchanged zeolites. At 753 K the Cu2+-exchanged ZSM-5 zeolite with SiO2/Al2O3=23.3 and exchange level=100% showed a high and consistent activity for the reaction even at a contact time of 0.2–0.025 g.sec.cm−3 or GHSV=10000–80000 h-1. The IR, ESR, and TPD experiments made it possible to evaluate the number of Cu2+ ions which could adsorb NO molecules. It follows that the proportion of the copper ions available for NO adsorption is dependent on the zeolite structure, and the activity per cupric ion accessible to NO depends on the Al content of the parent zeolite.
17 citations
TL;DR: In this article, the catalytic activity of Y zeolites containing copper ions (CuY) for decomposition of nitrogen monoxide was enhanced through additional exchange of other metal ions or evacuation treatment around 923-973 K.
Abstract: Catalytic activity of Y zeolites containing copper ions (CuY) for decomposition of nitrogen monoxide was enhanced through additional exchange of other metal ions or evacuation treatment around 923–973 K. In the first case, Co3+ or Ni2+ ions increase the catalytic activity while Ca2+, Mn2+, Fe2+, and Zn2+ diminish the catalytic activity of CuY. In the second case, the catalytic activity of CuY evacuated at 973 K was twice that of CuY without the evacuation treatment, which is discussed in connection with the increment of Cu ions active for the decomposition.