The present invention belongs to the technical field of zeolite materials, and is specifically a high specific surface mesoporous-microporous composite BETA zeolite and a preparation method thereof. The present invention uses a small amount of BETA zeolite as a seed, adds a silicon source, an aluminum source, water, an organic template agent, etc. to make a wet gel, and then dries it to obtain a dry gel, and then crystallizes it in water vapor at a certain temperature and pressure, and finally removes the organic template agent at high temperature to prepare a high specific surface mesoporous-microporous composite BETA zeolite.
- A method for preparing a high specific surface mesoporous-microporous composite BETA zeolite, characterized by the following specific steps:
(1) Using BETA zeolite as a seed, adding a silicon source, an aluminum source, water and an organic template, preparing a wet gel in an alkaline system, and then drying to obtain a dry gel;
(2) Then crystallizing in water vapor at a certain temperature and pressure;
(3) Finally, removing the organic template at high temperature to prepare a high specific surface mesoporous-microporous composite BETA zeolite.
Wherein, the silicon source in step (1) is white carbon black, silica gel, water glass, silica sol or tetraethyl orthosilicate; the aluminum source is aluminum sulfate, aluminum nitrate or aluminum hydroxide; the amount of the aluminum source is calculated in molar ratio: Al₂O₃/SiO₂=0~0.023; the organic template is TEAOH, and the amount of the template is calculated in molar ratio: TEAOH/SiO₂=0.08~0.4. - The preparation method according to claim 1 is characterized in that the molar ratio of the base in the alkaline system is: OH/SiO₂=0.22~0.42.
- The preparation method according to claim 1 is characterized in that the crystallization in water vapor is carried out in a closed environment with water vapor, the water vapor pressure is 270kpa~1002kpa, the temperature is 130~180℃, and the reaction time is 5~72 hours.
- The preparation method according to claim 1 is characterized in that the high-temperature removal of the organic template after crystallization is to place the BETA zeolite in a muffle furnace for high-temperature roasting; the temperature is set from 5~10℃, and rises to 550~600℃ at a rate of 2~3℃/min, and is maintained at this temperature for 3~5 hours.
- The high specific surface mesoporous-microporous composite BETA zeolite molecular sieve obtained by the preparation method described in any one of claims 1 to 4 is characterized by being an agglomerate of nano-spherical particles, wherein the BET specific surface is 417~740 m²/g; the mesopore specific surface is 97~300 m²/g.
- The high specific surface mesoporous-microporous composite BETA zeolite molecular sieve according to claim 5 is characterized by having the following main characteristic X-ray diffraction characteristic spectral lines belonging to the Beta-type zeolite structure:
