摘要：

The effects of ion-exchange conditions (the pH, the copper concentration in solution, and the solution-to-zeolite volume ratio) and the Si/Al atomic ratio of HZSM-5 zeolite on the concentration and state of copper in bulk CuZSM-5 catalysts and on the catalytic activity in the selective reduction of NO with propane were studied. It was found that the concentration and state of copper in the catalysts essentially depend on the pH of the solution used for ion exchange and on the copper concentration in this solution. An increase in the solution-to-zeolite volume ratio has almost no effect on the above characteristics. Regardless of the Si/Al atomic ratio of zeolite and of the pH of solution, a maximum activity (NO conversion) of the resulting catalyst is attained even at an exchange level (Cu/Al) close to 100% (80–140%). The absolute value of this catalytic activity depends only on the reaction temperature and is equal to 22–31% at 300°C or 85–97% at 400–500°C. The above exchange level is

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