Granular activated carbon is divided into shaped and amorphous particles.Mainly withcoconut husk, fruit shell and coal as raw materials, through a series of production processes from fine processing.Products are widely used indrinking water、Industrial water, wine makingWaste gas treatment、Decolorization、desiccant、Gas purificationAnd other fields.High quality granular activated carbonanthraciteAs raw material, it is refined and processed by advanced technology, and its appearance is black amorphous particles;Having developedpore structure , good adsorption performance, high mechanical strength, easy repeated regeneration, low cost and other characteristics;It is used for purifying toxic gas, waste gas treatment, industrial and domestic water purification, solvent recovery, etc.
Activated carbon as porousAdsorbentIt is a kind of carbon raw materialactivationRear microfilmgraphiteAn amorphous substance consisting of microcrystals and hydrocarbons.Activated carbonDue to the different appearance, shape, raw materials, manufacturing methods and uses, the variety of.According to the external shape, it is usually divided into powder activated carbon and granular activated carbon.Powdered activated carbon is mostly wooden activated carbon, which fails to meet the use standards of some industries due to problems such as easy blockage of filter surface and difficulty in separation of powder.Therefore, granular activated carbon has received more and more attention and research. It has a certain shape, high mechanical strength, less dust pollution, advantages in preparation, storage and use, and is easy to meet the special requirements of different industries.However, the problems of high production cost and heavy pollution in the preparation of granular activated carbon have not been solved.Therefore, the development of a kind of granular activated carbon with low production cost, high mechanical strength and high adsorption efficiency will have important research significance and broad market prospects.[1]
Coconut shell granular activated carbon is made from high-quality coconut shell by a series of production processes.The appearance is black and granular, with developed pores, good adsorption performance, high strength, economy and durability.
The products are mainly used for the purification, decolorization, dechlorination, deodorization, desiccant, catalytic carrier and other aspects of drinking water, purified water, tap water, liquor making, beverage and industrial water.
Fruit shell granular activated carbon
Fruit shell granular activated carbon is made from peach shell, apricot shell and other fruit shells by a series of production processes.The appearance is black and granular, with developed pores, good adsorption performance, economy and durability.
The products are mainly used for purification, purification and decolorization of boiler water, industrial water, domestic water, beverage water and other industrial wastewater in power plants.
Granular activated carbon from coal
Granular activated carbon from coal has complete specifications, which can be divided into shaped and amorphous particles.Unshaped particle products are mainly used for purification, purification and decolorization of industrial water and other industrial wastewater, which can effectively purify domestic sewage and chemical sewage.The shaped particle products are mainly used for gas treatment, sewage treatment, desulfurization and denitrification, solvent recovery, nitrogen generator/air separation equipment, spraying workshop, etc.
Preparation of raw materials
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There are a wide range of raw materials for preparing activated carbon. Carbon containing materials can be used as raw materials for preparing activated carbon. These raw materials can also be used for preparing granular activated carbon. They are mainly divided into two categories: coal based raw materials and wood based raw materials.Coal raw materials mainly include anthracite, slime, lignite, petroleum coke and coal based materials;Wood raw materials mainly refer to walnut shell, wood, fruit shell, bamboo, crop straw, carbon containing waste residue, etc.In addition, granular activated carbon with good quality can also be prepared by separating carbon powder and waste polystyrene foam with dust.[2]
Preparation method
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The preparation methods of granular activated carbon are mainly divided into two categories: 1) carbon activation without adding binder;2) The carbon precursor is processed and shaped by adding binder, and then the carbon activation process is carried out.
Binder free method
The preparation of granular activated carbon without adding binder can be divided into two types: one is to directly activate natural wood materials with a certain shape and size to obtain amorphous granular activated carbon;The second is to prepare granular activated carbon by chemical activation method without adding binder.
Abundant molded natural woody plant materials, such as coconut shells, walnut shells, olive stones and other fruit shells and nuts, can be directly prepared by physical or chemical activation of amorphous granular activated carbon.Poinern et al. prepared granular activated carbon from macadamia nut shell by high-temperature carbonization and carbon dioxide activation, and discussed the effect of activation temperature on gold adsorption of activated carbon.The results show that high temperature activation is beneficial to increase the gold absorption capacity of granular activated carbon.He Deliu et al. invented the technology of producing wooden amorphous granular activated carbon by phosphoric acid method. Through pre crushing, soaking, floating and drying carbonization at low temperature of raw materials (mainly fruit shells and kernels), products with high strength and adsorption power can be obtained after activation.The results show that the particle size of raw material is 20~40 mesh, which is conducive to the penetration of activator. Compared with the zinc chloride method, the strength of amorphous carbon is improved, and the iodine value is>950 mg/g, and the B caramel color is>100%. Compared with the physical method, the production cost is reduced by 40%.
The chemical activation method for self forming granular activated carbon is a method of adding a certain amount of chemicals into the carbonaceous raw materials, fully kneading and plasticizing to produce adhesive and plasticizing substances such as tar, which can be formed without adding additional binders, and is completed in one step by heating carbon activation.The chemicals used to prepare granular activated carbon mainly include ZnCltwo、HthreePOfour、KOH、NaOH、HtwoSOfour、CaCltwo、KtwoCOthreeEtc.Different chemical activators have different activation mechanisms for raw materials.
Binder method
add tobinderIt is mainly for the preparation of formed activated carbon to solve the problems such as non cohesiveness of raw materials, difficulty in forming, and unsatisfactory product strength and surface smoothness.The type and amount of binder greatly affect the strength and adsorption performance of activated carbon.The addition of binder often blocks part of the pores of granular activated carbon, resulting in the improvement of mechanical strength and the reduction of its adsorption performance.Common binders include coal tar, starch, wood tar, sulfite pulp waste liquidclay, waste molassesCarboxymethyl cellulose、resinClass, etc.
Coal has the advantages of high carbon content, rich resources and low price, and is widely used as raw material for the preparation of granular activated carbon.At present, the raw coal used for manufacturing coal based granular activated carbon is non caking and weakly caking coal, such as anthracite, weakly caking coal, lignite, etc., so a certain amount of binder needs to be added to the raw coal to make it compacted.Because of the high pitch content of coal tar and its strong adhesion to pulverized coal, most coal based activated carbon plants in China use coal tar as binder.Du Yaping and others used coal tar as the binder of petroleum based granular activated carbon, kneaded with anthracite, extruded and activated to produce granular activated carbon with high mechanical strength and developed micropores, which can be used as an adsorbent for air or water purification.
In addition to coal raw materials, researchers have also conducted a lot of research on the preparation of granular activated carbon from wood raw materials and other raw materials.Xia Hongying et al. prepared granular activated carbon with tobacco stem waste as raw material and wood tar as composite binder by steam and carbon dioxide activation methods respectively.The results show that when activated at 900 ℃, the granular activated carbon prepared by steam method is microporous, and the BET specific surface area is 1037 mtwo/g. The total pore volume is 0.8152 mL/g;The activated carbon produced by carbon dioxide method is also microporous, with a specific surface area of 947.81 mtwo/g. The total pore volume is 0.48 mL/g, but the yield is higher than that of steam method.[1]
application
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Granular activated carbon, due to its huge specific surface area and developed pore structuremechanical strengthIt is high, acid and alkali resistant, stable in nature and other advantages, and is widely used in chemical industry, food, medical treatment, national defense and other fields, especially in environmental protection. Activated carbon, as a gas and liquid phase adsorbent, has important research significance in treating air pollution and water pollution.Granular activated carbon adsorbent is used to remove pollutants in water and air by physical adsorption, chemical adsorption and oxidation catalysis of activated carbon.
High efficiency of granular activated carbon as clean energyAdsorbent, already fornatural gas、hydrogenThe storage and transportation of clean energy will provide greater economic benefits.At the same time, granular activated carbon is also widely used for gas refining: unpleasant odors in public or residential places, such as the smell of restaurant food, the smell of paper and sweat in libraries and offices, are unpleasant. Granular activated carbon can be used to purify indoor air;Air in industrial plants, such as food processing, pharmaceutical manufacturing or precision instrument roomssmoke、dustanda stimulusComposition, which will affect the health of workers or cause oxidation and corrosion of precision instruments. Granular activated carbon can be used to purify and remove impurities;The gas emitted from coal acid plants, chemical plants and automobile exhaust contains various organic solvents, inorganic and organic sulfides, hydrocarbons, organic mercury compounds and other harmful components. Direct emission will seriously pollute the atmosphere and affect human health. Granular activated carbon can be used for efficient adsorption, recovery and re emission;Active carbon is used to purify the air in the cold storage room and fruit warehouse to achieve circular ventilation and reduce ethylene concentration, so as to extend the storage period of fruits;The radioactive gases such as krypton and xenon emitted from nuclear power plants can cause human carcinogenesis and plant death. They must be absorbed by activated carbon before being discharged;In addition, granular activated carbon is widely used in military to make gas masks and industrial respirators.
In the application of liquid phase adsorption, granular activated carbon is widely used in drinking water purification, industrial wastewater treatment, wine making, decolorization, deodorization, deodorization, desiccant, solvent recovery and other fields.For the increasingly serious water pollution, it not only destroys the aquatic ecosystem, but also poses a major threat to human health and social economy.Granular activated carbon has the advantages of strong adsorption performance, easy regeneration and reuse, and can remove substances and organics that produce odor in water, such as benzene, phenol, chlorine, pesticides, detergents, trihalomethanes, etc.In addition, heavy metal ions such as silver, cadmium, copper, mercury, antimony, arsenic, bismuth, tin, lead and chromate can also be effectively removed.
Granular activated carbon can also be used ascatalyzerAndcarrier, in terms of catalysis andelectrochemistryIt is widely used, such as catalytic degradation of ozone by granular activated carbonMetal catalystAnd the production of supercapacitorEtc.[1]
