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, Activated carbon fiber Beijing 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. Activated carbon fiber 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.

Activated carbon fiber major The high reliability makes users no longer worry about unexpected shutdown, which is the confidence brought by UOP molecular sieve. Traditional molecular sieves can be used as desiccants, adsorbents and ion exchangers. UOP also provides high silicon zeolite series molecular sieves for non-traditional applications, including molecular sieves to remove organisms that affect the taste of food and drinks or cause odor. Zeolite molecular sieves have crystal structure and characteristics, the surface is a solid skeleton, and the internal holes can play the role of adsorption molecules. There are channels between the holes to connect with each other, and molecules pass through the channels. Due to the crystalline nature of the pores, the pore size distribution of the molecular sieve is very uniform. Molecular sieves selectively adsorb molecules according to the size of holes in their crystals, that is, they adsorb molecules of a certain size and repel molecules of larger substances, so they are vividly called "molecular sieves". The adsorption or repulsion function of molecular sieves is affected by the molecular electricity. Synthetic zeolite has the special function of selective adsorption according to the size and polarity of molecules, so it can dry or purify gas or liquid, which is also the basis of molecular sieve for separation. Activated carbon fiber Beijing Synthetic zeolite can meet the extensive demand of industry for adsorption and selective products, and is also widely used in industrial separation to synthesize zeolite molecular sieves. Advantages of UOP molecular sieve

Activated carbon fiber major There are cavities and channels in the crystal structure of zeolite with large adsorption capacity, whose volume accounts for more than 50% of the total volume of zeolite crystals. Moreover, the micropores of zeolite are evenly distributed, and the pore size is small, which is equivalent to the molecular size of general substances. The internal surface area of zeolite crystals can reach more than 1000 square meters. Therefore, the adsorption capacity of zeolite is particularly large. The main material of honeycomb zeolite adsorbent is natural zeolite. The manufacturer of zeolite is composed of silica Inorganic microporous material composed of al_2o_3 and alkaline metal or alkaline earth metal, with inner pore volume accounting for 40-50% of the total volume and specific surface area of 100-500 m2/g, is characterized by high temperature resistance, non flammability, good thermal stability and hydrothermal stability. It is an efficient molecular sieve carrier with good adsorption performance, no secondary pollution, and can be regenerated at high temperature. Compared with honeycomb activated carbon, its performance is about 25% of its efficiency, However, it is widely used in the fields of adsorption, separation, catalysis and environment due to its high temperature resistance and difficult ignition. It is more suitable for the treatment of organic waste gas with large air volume and low concentration.

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. Activated carbon fiber Direct selling 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. Activated carbon fiber 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.

Activated carbon fiber major The addition of retention aids in the wet end of paper making is an important way to improve filler retention, which has been widely used in industrial production. Some studies reported that clinoptilolite (particle size 0.5-2 μ m) was used as a microparticle retention aid to compare the retention effect with silica and bentonite microparticle retention aid systems. The retention effect of clinoptilolite retention aid is equivalent to that of the silica microparticle retention aid system with the same dosage, which is far better than that of the bentonite microparticle retention aid system. And the use of zeolite as paper filler eliminates the need for additional microparticle retention aids. It is also reported that the retention rate of TiO2 nanoparticles can be significantly improved by using zeolite molecular sieves as retention aids in the preparation of photocatalytic paper. Compared with starch and cationic polymer, zeolite molecular sieve microparticle retention aids have better effects on improving the retention and drainage properties of paper stock and improving the uniformity of paper. Activated carbon fiber major The use of zeolite particle retention aids can effectively avoid flocculation between fibers, and help to form fiber particle fiber flocculating particles. In addition, it can also support titanium dioxide nanoparticles.

Activated carbon fiber major Due to its large pore size, mesoporous materials have become a good carrier for molecular reaction with large size. However, the pore wall of mesoporous materials is amorphous, so their hydrothermal stability and thermal stability cannot meet the harsh conditions required for petrochemical applications. Because there are metal ions with low electricity price and large ion radius and water in the combined state, water molecules are continuously lost after heating, but the crystal skeleton structure remains unchanged, forming many cavities with the same size. The cavities are connected by many micropores with the same diameter. These tiny holes have uniform diameters, which can adsorb molecules smaller than the diameter of the hole into the interior of the hole, By excluding molecules larger than pores, molecules with different shapes, diameters, polarities, boiling points and saturation levels can be separated, Activated carbon fiber Direct selling It has the function of "screening" molecules, so it is called molecular sieve. At present, molecular sieves are widely used in metallurgy, chemical industry, electronics, petrochemical industry, natural gas and other industries.