Activated carbon is a very widely used industrial adsorbent. It is made of charcoal, various kinds of fruit shells and high quality coal as raw materials. It is made by a series of processes, such as crushing, screening, activating, rinsing, drying and screening of raw materials by physical and chemical methods.
1. What is activated carbon
It is an irregular arrangement of microcrystalline carbon, with fine holes between cross connections and carbon tissue defects during activation. Therefore, it is a kind of porous carbon with low accumulation density and larger surface area. Active carbon is odorless, tasteless, sand free, insoluble in any solvent, has selective adsorption capacity to various gases, and has high capacity for adsorption of organic pigments and nitrogen containing bases. The total surface area of each G can reach 500 to 1000m2. The relative density is about 1.9 ~ 2.1, and the apparent relative density is about 0.08 ~ 0.45.
2. Type of activated carbon
Activated charcoal is composed of apricot, coconut, walnut shell, coal, coal tar and charcoal from the raw materials. From the application form, it is mainly divided into powdered activated carbon, granular activated carbon and fibrous activated carbon.
(1) powdered activated carbon (PAC)
The particle size of powdered activated carbon is about 10-50um, which is directly added to water and is generally combined with coagulant. PAC is cheap, easy to add, quick to invest, especially for short term and sudden pollution. However, because the regeneration technology has not yet been solved, there is a cost problem when a large number of activated carbon is needed, so it is only used for low dosage or intermittent treatment.
(2) granular activated carbon (GAC)
It can also be divided into spherical activated carbon, polymer coated activated carbon, soaked activated carbon and other types. The application of GAC to remove organic pollutants like halides in tap water is the most widely used method to reduce carcinogens in water and is widely used in various filters and purifier.
(3) activated carbon fiber (ACF)
Also known as fibrous activated carbon, it is a new type of highly efficient adsorption material made from fibrous precursor, activated by a certain process of carbonization. It has developed microporous structure and various functional groups, and the adsorption performance is obviously better than that of conventional PAC and GAC. The microporous structure of activated carbon fibers is narrow and uniform, and the diameter of the micropores is in 1-2nm. The adsorbate can be adsorbed and deformed directly on the micropores exposed to the surface of the fiber. The adsorption speed is faster and the specific surface area is larger. Therefore, the adsorption capacity is larger, and because it can be processed into different shapes, such as felt, cloth, paper and so on. With its acid and alkali resistance, it has attracted extensive attention and in-depth research since its advent.
3. Cleaning of activated carbon
Activated carbon is adsorbed and adsorbs some impurities and odors, so it is not necessary to clean at ordinary times. After a period of time, insolation in the sun can achieve a clean effect and can be used again and again; until the activated carbon is less, it shows that it is consumed.
4. Maintenance of activated carbon
If the activated carbon is used for a certain period of time, its adsorption capacity will reach a bottleneck and affect its function, so it is necessary to keep the products in the sun, keep the activated carbon dry and reuse, to prolong the service life of the product.
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