METHODS OF PREPARATION OF METAL EXCHANGED ZEOLITES

Methods of preparation of metal exchanged zeolites by ion exchange of metals such as copper, iron or manganese with aluminosilicates and silicoaluminophosphates such as CHA, MFI, BEA and small pore zeolite frameworks are disclosed. The method uses a combination of a liquid reaction medium with a gaseous reaction medium wherein the metal to be exchanged is preferably in the elemental metallic form and the gaseous reaction medium comprises at least carbon dioxide. These metal exchanged zeolites are useful as catalysts for the reduction of oxides of nitrogen from gaseous streams by Selective Catalytic Reduction with ammonia or urea. 公开了通过金属诸如铜、铁或锰与铝硅酸盐和硅铝磷酸盐诸如CHA、MFI、BEA和小孔沸石骨架的离子交换来制备金属交换沸石的方法。该方法使用液体反应介质与气体反应介质的组合，其中要交换的金属优选为处于元素金属形式并且气体反应介质至少包括二氧化碳。这些金属交换沸石用作通过用氨或脲选择性催化还原来还原来自气流的氮氧化物的催化剂。