Dalian Institute of Chemical Physics Made Progress in Study on Controllable Post-treatment of Si-Al Zeolite

The CAS Dalian Institute of Chemical Physics in the study on controllable tuning of the properties of Si-Al zeolite has for the first time realized the bridging of desilication and dealumination processes.

The dealumination-related post-treatment aims to regulate the aluminum centers based on the existing composition and structual units of the Si-Al zeolite. This technology has been studied and developed in more than a half century,with its representative approach ― the hydrothermal treatment ― being extensively adopted in the course of Si-Al zeolite production. However, the dealumination approach has its limitations in terms of the role of microporosity in adjusting the property of the Si-Al zeolite.This study has for the first time successfuly achieved the bridging of the desilication and the dealumination methods. By menas of the simple and viable steam treatment coupled with alkaline treatment, it is possible to overcome the dual restrictions arising from high aluminum content and large grain size, resulting in forming the concentrated and controllable multiple microporousmesoporous structure inside the high-aluminum MFI type zeolite to retain abundant strong acid sites and good hydrothermal stability. This research work, after having overcome the view dominating both at inside and outside of China that desilication and dealumination operations cannot be bridged, has providing a rich “tool box” for the development of a low-cost, an operation-reliable,and an applicable in massive scale catalyst preparation method. Furthermore, the said research has revealed that the structure, the location of non-framework Al species, as well as the interaction between framework ions can play important roles in the course of debugging and changing the zeolite property, which has brought about a new insight in the traditional research on the Si-Al zeolites.