Encyclopedia of Building Materials: An Analysis of the Production of Zeolite Molecular Sieve with Kaolin

After the article "Research on the production of zeolite molecular sieve with kaolin" was published on July 4 last year, it attracted the interest of many ceramic enterprises. They also want to know about application issues.

For this reason, we wrote this article as a sister article for the production of zeolite molecular sieves with kaolin.

Zeolite molecular sieve is the only shape selective adsorption, catalytic material, not only is expected to reduce the generation of by-products by selective catalysis, improve the utilization rate of reaction raw materials, but also through structural adjustment, load modification and other means to form the production of functional catalytic materials, so more and more research and use to many fields, the use is more and more widely.

Zeolite molecular sieves represented by A type, with a silicon-aluminum ratio close to 1, have the highest cation content, large pore volume, large specific surface area and small pore size, and are mainly used for purification, drying, separation and ion exchange processes. Such as ethylene dehydration, air oxygen, washing process ion exchange. The medium silicon series zeolite molecular sieve is represented by X and Y molecular sieve, which is mainly used as catalyst and catalyst carrier, and has the dual function effect of solid acid and metal. Because of its unique uniform pore size system, it plays a shape selective catalytic effect on reactants and reaction products in the catalytic process, so it has higher activity and selectivity. It has been widely used in petroleum cracking, hydrocracking, isomerization, reforming, toluene disproportionation and other industries. The high silica series zeolite molecular sieve is represented by the ZSM-5 type, with high silicon-aluminum ratio, good thermal stability and acid resistance, and because of its high density framework structure and straight tube channel system, it is not easy to form carbon and lose activity in the catalytic reaction process. It has been used for methanol to gasoline and hydrocarbon isomerization, and its application range is expanding. Silica type molecular sieve in addition to the ZSM-5 type molecular sieve similar pore structure, the surface almost does not contain hydrocarbon, has good hydrophobic and lipophilic, can be used for water and organic phase separation, especially from the water phase adsorption of trace organic matter, to prevent pollution and purification with special effects.

Recent studies have shown that zeolite molecular sieves also have acid resistance, high temperature resistance, radiation resistance and other properties. These physicochemical properties give zeolite molecular sieves unique functions.

The adsorption capacity of zeolite to organic pollutants mainly depends on the polarity and size of organic molecules, and organic molecules containing polar groups can have strong adsorption with the surface of zeolite molecular sieve. Using this principle, we can decolorize waste water, aquaculture wastewater, aniline-containing wastewater, slaughtering wastewater, papermaking wastewater, printing and dyeing wastewater, remove trace phenol and benzene, remove radioactive substances from water, remove radioactive substances from solids, remove ammonia nitrogen, arsenic, phosphorus, aluminum from industrial and domestic wastewater, and treat heavy metals (lead, nickel, zinc, cadmium, copper, iron, manganese, mercury), etc, for example, the high concentration of wastewater discharged from papermaking wastewater can reduce CODCR from 2800~3500mg/l to 450~960mg/l. Aniline is an important intermediate in the production of dyes, pesticides and pharmaceuticals. However, aniline is a toxic substance that is difficult to biodegrade. It is very toxic. It is quickly absorbed by the human body through the skin and inhalation of steam, which will produce purple spot disease. The maximum adsorption capacity of aniline adsorbed by zeolite molecular sieve can reach 10 mg/g, and the adsorption rate is 93%.

Ammonia nitrogen in natural water mainly comes from protein decomposition, or ammonia nitrogen, nitrite nitrogen and nitrate nitrogen are transformed into each other under certain conditions due to nearby pollution sources, which is harmful to human body. Ammonia nitrogen enters human body and synthesizes nitroso compounds to induce cancer. Therefore, it is necessary to take measures to remove ammonia nitrogen to improve the quality of drinking water. In addition to industrial and mining industrial wastewater and urban domestic wastewater also remove ammonia nitrogen application has a greater possibility.

Hydrocarbons, carbon monoxide, hydrogen sulfide, etc. emitted from chemical industry, light industry and other industries are the main harmful gases that pollute the atmosphere. Zeolite molecular sieves have good adsorption and purification functions for these gases, especially in the low temperature range, which other adsorbents do not have. Using the adsorption properties, acid resistance and high temperature resistance of zeolite molecular sieves, SO2 in factory exhaust gas can be adsorbed, and the adsorption capacity can reach 100~120 mg/g, the removal rate can reach more than 90%.

When ammonia is recovered from synthetic ammonia exhaust gas and nitrogen oxides such as CO and NO are used as automobile exhaust gas treatment agents, harmful gases can be adsorbed and environmental pollution can be reduced. Zeolite molecular sieves have a good adsorption effect on sulfur oxygen, nitrogen oxygen, hydrogen sulfide and ammonia, and are widely used in deodorizing adsorbents. NH3 and H2S are the main odor gases in the refrigerator, and the removal rate of NH3 and H2S can reach 90%.