Principles and types of Zeolite

Absorption features: molecular sieve adsorption material from physical adsorption (van der Waals forces), which has a strong internal crystal cavities polarity and Coulomb field of polar molecules (such as water) and unsaturated molecules show a strong adsorption capacity.
Screening function: very uniform pore size distribution of the molecular sieve, only molecular diameter smaller than the diameter of the hole before substance may enter bughole internal molecular sieves.
By order of priority and size to distinguish molecular adsorption of different substances, so the image is called "molecular sieve."
Type: synthetic zeolite molecular sieve zeolite and two natural. Most ① natural zeolite formed by volcanic tuffs occur and tuffaceous sedimentary rocks in marine or lacustrine environment reaction. Have been found to have more than 1000 kinds of zeolite mineral, the more important ones are 35 kinds, often with clinoptilolite, mordenite, erionite and chabazite, etc. Mainly in the United States, Japan, France and other countries, China also found that a large number of mordenite and clinoptilolite deposits, Japan is the largest country in the natural zeolite mined. ② due to natural zeolite subject to resource constraints, from the beginning of the 1950s, a large number of synthetic zeolites.
Goods zeolite crystal structure common prefixes Digital classify the different molecular sieves, such as type 3A, 4A type, 5a zeolite molecular sieves. 4A Class A type that table, aperture 4Å ;. A type of zeolite containing Na +, referred to as Na-A, if one is Na + K + replacement, pore size of about 3Å ;, is the 3A molecular sieve; Na-A if there is more than one third of the Na + Ca2 + exchange, aperture is about 5Å ;, is the 5A molecular sieve.

Application of molecular sieves 4A

Detergent additives: zeolite 4a as a detergent additive main function is to produce calcium ion exchange water softening, remove dirt and prevent redeposition. 4A Zeolite is currently applied on behalf of the largest builders of phosphorus and most mature product. 4A Zeolite replace sodium tripolyphosphate as detergent additives to solve the environmental pollution has a major role. 4A Zeolite forming agent can also be used soap, toothpaste friction agent.
Sewage: 4A molecular sieve can remove sewage NH3-N, and Pb2 +, Cu2 +, Zn2 + ,, Cd2 + and so on. Industry, agriculture, animal husbandry and aquatic civilian discharged wastewater containing ammonia nitrogen, not only endanger the survival of fish, in the farming environment pollution, and promote algae growth, leading to blockage of rivers and lakes. 4A molecular sieve due to high selectivity of NH4 + exchangeable, has been successfully applied in the field. Sewage from metal mines, smelters, metal surface treatment and chemical emissions from industry and other sectors, which contains heavy metal ions harmful to human health. 4a zeolite molecular sieves with sewage in addition to those qualified to ensure the water quality, but also the recovery of heavy metals.
Other uses:
(1) Water ---- hard water softener, can replace the current widespread use of sulfonated coal, thereby reducing costs;
(2) Metallurgical Industry ---- separating agent, separation, extraction of brine potassium, rubidium, and cesium. In industry for the enrichment, separation and extraction of metals and other processes;
(3) petrochemical industry ---- catalysts, desiccants, adsorbents;
(4) ---- agricultural soil conditioner;
(5) Pharmaceutical ---- silver zeolite antimicrobial agent.

Some catalytic behavior of molecular sieve dehydration in ethanol amination reaction

Aliphatic amines is an important raw material of pesticides, pharmaceuticals, dyes and other industries. Its main synthetic methods ammoniated alcohol dehydration and alcohol dehydrogenation amination, an AI:. O, as a catalyst since production has since been put in since the early 1960s. Its alcohol conversion rate is acceptable, but a less selective amine. Binary and ternary metal oxide catalytic systems studied many reports ['', due to poor performance, the industry .zSM a selective 5 zeolite came after an attempt to take advantage of its role in improving the shape-selective primary amine has not been adopted Research work has been reported ['a 6'. Selective dehydration of methanol amination reaction of methylamine is indeed improved. For alcohol-containing C-C bond, 3a zeolite molecular sieves dehydration amination reaction catalyst as a research work has not yet commenced. This article focuses on the study of various zeolite acidity, pore structure on ethanol dehydration amination. Got some interesting results. Experiment 1 reagent and preparing zeolite powder original NaY (Wenzhou Chemical), NaM (Nanjing plant 5a zeolite molecular sieves  and NaZSM a 5 (Nankai Chemical) were treated with 10% NH; NO. Solution, 1 mol / L and 0.1 mol L hydrochloric acid solution / Maid change at a certain temperature for several hours to obtain sodium hydrogen zeolite washing, suction filtration, drying, take part NaHY, NaHM, NaHzSM a 5 respectively 5% LaC13, La 10% MgclZ solution obtained corresponding exchange, Mg · zeolite, washing, suction filtration, dried and set aside. Pu 2 test zeolite catalyst

functions and features of Molecular sieve

The porous material has been widely used in many fields, such as the main catalytic microporous molecular sieve material, adsorption and ion exchange material separation materials plays an increasingly important role in oil processing, petrochemicals, fine chemicals, and household chemicals .
molecular sieves(also known as a synthetic zeolite) is a microporous aluminosilicate crystalline silicon. It is made of silicon oxide, aluminum oxide tetrahedra basic skeleton structure, there is a metal cation in the crystal lattice (such as Na +, K +, Ca2 +, Li +, etc.), in order to balance the negative charge excess crystals. According to their type of zeolite crystal structure is divided into: A type, X-type, Y type.
Zeolite relevant standards:
"3a molecular sieve" "4A molecular sieve" "5a molecular sieve and test methods" "13X molecular sieve"
"Water assay method static sieve" "sieve dynamic water assay method"
"Granular sieve size determination," "Determination of bulk density of molecular sieve" "sieve crush strength test method", "Standard Test Method for molecular sieve desiccant cooling systems with anti-wear performance," "Determination of dynamic zeolite adsorption of carbon dioxide."
"Industrial activated alumina," "air separation plant with activated alumina acceptance technical conditions"

PSA nitrogen plant design basis

   Adsorption matrix for all types of adsorbents, such as: aluminum plastic, silicone, 3a zeolite molecular sieves activated carbon and molecular sieves.  Among PSA nitrogen means they use various types of molecular sieve adsorbents (zeolites, carbon molecular sieves), various types of molecular sieves have specific selective adsorption, such as nitrogen is often used 3A carbon molecular sieve oxygen, and adsorption H20, C02 multi-use 13X zeolites.  PSA Nitrogen Generator works: clean pressurized air (oxygen and nitrogen mixed gas) through some sort of carbon molecular sieve, most of the remaining traces of oxygen and water is a molecular sieve adsorption, adsorption of nitrogen is unable to be discharged This nitrogen adsorption stage.   While reducing the pressure to atmospheric or subatmospheric pressure, the adsorption capacity of the molecular sieve oxygen decreased oxygen which is resolved in a compressed state of the adsorbed water and the regeneration is parsed (oxygen) phase.  Molecular sieves can be parsed and nitrogen adsorption phase of the next cycle, the cycle is repeated to obtain a certain purity of nitrogen, while some of the purity of the oxygen enriched air. 

The practical application of zeolite sieves molecular activation

Zeolite sieves molecular activation is emptying device for PSA oxygen concentrator,zeolite sieves molecular activation including two adsorption towers, zeolite sieves molecular activation is two is arranged in the adsorption tower below theelectromagnetic valve, 3a zeolite molecular sieves vent duct activated zeolite powder, zeolite sieves molecules to activate the vent valve and a vacuum pump; the vent duct is connected to one end ofthe two electromagnetic valve are respectively used in pipeline, zeolite sieves molecular activation two the electromagnetic valve is connected to the other end ofthe pipe is respectively for the adsorption tower; zeolite sieves molecular activation of the vent pipe are connected by pipeline are respectively connected to the vent valveend and one end of the zeolite powder. synthetic zeolite powders the other end of the other end ofthe activation of sieves vent valve and the vacuum pump is connected with a muffler.Activated zeolite powder by the technical proposal, the utility model by adsorption venttower in the add a vent valve, the device switches vent pre vent valve open, zeolitesieves molecular activation by the adsorption tower pressure difference inside and outside the internal exhaust gas vent part, zeolite sieves molecular activation of remaining gas use the vacuum pump; reduce shortens working period of vacuum pumps, vacuum pump load, prolong the service life of vacuum pump.