From low silica zeolite to high silica zeolite（2）
Due to the increase of types, the diversification of structure [secondary structural units (SBU) and pore structure openings and the impact on molecular sieve structure and important properties such as thermal and hydrothermal stability (700~1300°C), acidity (strength and concentration), The improvement of understanding of the influence laws of surface hydrophilicity and lipophilicity, diffusion and adsorption performance, and ion exchange performance has prompted a number of molecular sieves to enter the field of industrial application. Type (Na, K, Ba type) Y type (Na, Ca. NH4 type), L type (K, NH4 type), Ω type (Na, H type), "zeolon" large pore mordenite (H, Na type) ), ZSM-5 type, F type (K type), W type (K type), etc., natural zeolites such as mordenite, chabazite, erionite and clinoptilolite. These molecular sieves have been widely used in the following three fields: 1. Adsorption and separation, such as drying, purification of gas and many separation processes such as n-paraffin, xylene isomer, O2, N2 in the air. Separation from inert gas, etc.; ② Catalysis field, it is the most important catalytic material in petroleum refining and petrochemical industry, coal chemical industry and fine chemical industry; ③ Ion exchange, one of the most important uses of molecular sieves (type A and X) It is mainly used in the detergent industry as the main auxiliary agent, the treatment and storage of radioactive waste, and the environmental protection treatment of factory and mine waste liquid.
