Molecular sieve has clear pore cavity distribution, extremely high internal surface area (600m2/s), good thermal stability (1000 ℃), and adjustable acid site center. The acidity of molecular sieve mainly comes from three coordinated aluminum atoms and aluminum ions (AlO)+on the framework and in the pores. OH based acid sensitive site center on molecular sieve HY obtained by ion exchange, Ganzhou The aluminum ions outside the framework will strengthen the acid site and form the L acid site center. Polyvalent cations such as Ca2+, Mg2+and La3+can show the acid site center after exchange. The reduction of transition metal ions such as Cu2+and Ag+can also form acid site centers. In general, the higher the Al/Si ratio, the higher the specific activity of OH group. The modification of zeolite acidity can introduce protons through direct exchange of dilute hydrochloric acid. This method often leads to dealumination of molecular sieve framework. So NaY will become NH4Y and then HY. Because there are uniform small internal pores in the molecular sieve structure, when the molecular linearity of reactants and products is close to the pore size of the crystal, the selectivity of the catalytic reaction often depends on the corresponding size of the molecule and pore size. major This selectivity is called shape selective catalysis. There are two mechanisms leading to shape selectivity. One is caused by the difference of diffusion coefficient of molecules participating in the reaction in the pore cavity, which is called mass transfer selectivity; The other is caused by the space limitation of the transition state of the catalytic reaction, which is called transition state selectivity.

High silica zeolite type molecular sieves, this kind of zeolite has a series, and ZSM-5 is widely used, with ZSM-8 and ZSM-11 having the same structure; The other group is ZSM-21, ZSM-35 and ZSM-38. ZSM-5 is often called high silica zeolite, with the Si/Al ratio up to 50 and ZSM-8 up to 100. This group of molecular sieves also shows hydrophobic characteristics. production Their structural units are similar to those of mordenite, consisting of pairs of five membered rings, with no cage like cavities and only channels. ZSM-5 has two sets of cross channels, one is straight through, the other is zigzag perpendicular to each other, both formed by ten yuan rings. The channel is oval and its window diameter is (0.55-0.60) nm. major Zeolites belonging to the high silicon group also have silicalite-1 of all silicon type, which has the same structure as ZSM-5, and silicalite-2 is the same as ZSM-11.

Zeolite molecular sieve is a kind of excellent adsorbent, which is widely used in the production of basic organic chemical industry and petrochemical industry, as well as in the treatment of harmful gases nox、co、co2，nh3，ccl4、 Purification of water vapor and gaseous hydrocarbon waste gas; As well as air purification and deodorization in biochemical industry, paint industry, underground places, leather factories and animal breeding places; Adsorption of flue gas odor, removal of mercury vapor, etc. The factors affecting the purification efficiency of honeycomb zeolite molecular sieves are absorption and desorption. If the waste gas adsorbed on the runner cannot be completely desorbed, the runner will become saturated after a long time, which will affect the adsorption efficiency of the zeolite runner, major The service life of zeolite will be directly affected over time.

High honeycomb zeolite molecular sieve content The zeolite content of the zeolite runner is proportional to the adsorption concentration efficiency, major Therefore, when choosing to purchase zeolite runner, the matching zeolite content should be selected in combination with the emission concentration of enterprise exhaust gas pollutants. 2、 With good hydrophobicity, choose to purchase zeolite with large specific surface area. 2) Select inspection equipment to test the hydrophobicity of equipment production When the air humidity is greater than 60%, calibrate the equipment. If the equipment is blocked and the machine works abnormally, it indicates that the equipment has poor hydrophobicity, and you should carefully consider whether to purchase the equipment.

With the continuous deepening of research, honeycomb zeolite molecular sieve has gradually moved from laboratory to industrial practical application. Due to its powerful performance, it can be integrated with the reactor, Ganzhou In membrane catalytic reaction, the reaction is coupled with separation. At present, the application fields of zeolite membrane are pervaporation, gas separation and membrane reactor. It is the needs of human practical activities and the development of application fields that constantly promote the development of zeolite molecular sieves. From natural zeolite to synthetic zeolite, from low silica zeolite to high silica zeolite; From silicoaluminium molecular sieve to aluminophosphate molecular sieve; From super micropore to mesoporous material; major The development from inorganic porous frameworks to MOFs, as well as the recent emergence of macroporous materials, has effectively improved the yield, reduced the synthesis cost and environmental pollution.