What is activated carbon? How to choose activated carbon?

Another performance of the adsorption capacity of activated carbon is the ability of decolorization. Activated carbon has the magical ability of turning colored liquid into light or colorless.

What is activated carbon? How to choose activated carbon?

What is activated carbon

Activated carbon is a kind of black powdery, granular or pelletized or amorphous carbon with porous structure. The main component is carbon, and also contains a small amount of oxygen, hydrogen, sulfur, nitrogen and chlorine. It is mainly made of wood, shell and coal by high temperature activation. Carbon is the most stable element in nature, so is activated carbon. The pore structure of activated carbon is developed, with large surface area (500-1000m2 / g), even higher, and strong physical adsorption performance, which can adsorb gas, liquid or colloidal solid; for gas and liquid, the quality of adsorbed substance can be close to the quality of activated carbon itself. Its adsorption is selective, and non-polar substances are easier to adsorb than polar substances. In the same series of substances, the substances with higher boiling point are easier to be adsorbed, the higher the pressure, the lower the temperature, the higher the concentration, and the greater the adsorption capacity. On the contrary, reducing pressure and increasing temperature are beneficial to gas desorption.

Activated carbon is often used for adsorption, separation and purification of gas, recovery of solvent, decolorizing agent of sugar solution, grease, glycerin, medicine, deodorant of drinking water and refrigerator, filter agent in gas mask, air purification, and carrier of catalyst or metal salt catalyst.

The role of activated carbon

Activated carbon is also called activated carbon black. It is a black powder or granular amorphous carbon. Let's take a look at the role of activated carbon.

Activated carbon has a strong role of "physical adsorption" and "chemical adsorption", which can adsorb some organic compounds and achieve the removal effect.

Now activated carbon is widely used in the air purification of automobile or indoor. Activated carbon is a kind of porous carbonaceous substance, its developed pore structure makes it have a large surface area, so it is easy to fully contact with toxic and harmful gases in the air. The strong adsorption force field around the activated carbon pore will immediately absorb toxic gas molecules into the pore, so the active carbon has a very strong adsorption capacity.

Main purpose:

1. New room: it is used to absorb formaldehyde, benzene series, ammonia, radon and other poisonous and harmful gases in the indoor air of the new house and continuously release to the air, and quickly remove the peculiar smell of decoration.

2. New furniture: it is used to absorb formaldehyde, benzene series and all kinds of peculiar smell.

3. Wardrobe, bookcase, shoe cabinet: dispel smell, detoxify, dehumidify, insect proof, deodorize, sterilize, preserve calligraphy and painting, etc.

4. Toilet: deodorization, sterilization, fresh air.

5. Floor: odor, moisture, mildew, moth proof, protect the floor from deformation.

6. Automobile: absorb all kinds of harmful gas in new car and all kinds of peculiar smell in old car.

7. Computers, household appliances, etc.: absorb and reduce the harm of radiation gas to people.

8. Office, hotel and other public places: purify air and eliminate peculiar smell.

How to choose activated carbon

At present, consumers don't know enough about activated carbon, and they often mistake activated materials such as bamboo charcoal, charcoal, coconut shell charcoal as activated carbon; secondly, low value-added carbon carvings and ordinary activated carbon as high-quality activated carbon. So when you buy, please make a distinction and don't be deceived. So, how to choose activated carbon?

Iodine value:

Iodine value is a performance difference of activated carbon. The iodine value of fruit shell, bamboo charcoal and coal are all in the hundreds. The iodine value of activated carbon raw materials is from 80085090095010001100mg / g, and the adsorption capacity is also different! Cost price is different! The activated carbon with the same iodine value has the best effect only with coconut shell.

Weigh by hand:

As mentioned above, in order to improve the adsorption performance of the activated carbon, only the pore structure can be made on the activated carbon as much as possible. The more pores, the looser the activated carbon is, the lighter the relative density will be, so the good activated carbon will feel lighter. In the case of the same weight packaging, the volume of the active carbon with good performance will be much larger than that of the poor activated carbon.

See decolorization capacity:

Another performance of the adsorption capacity of activated carbon is the ability to decolorize. Activated carbon has the magic ability to turn the colored liquid into light or colorless, which is actually caused by the reason that activated carbon adsorbs the pigment molecules in the colored liquid. Because of this characteristic of activated carbon, it is widely used in the production of brown sugar to white sugar in the sugar industry. Take two transparent cups, put pure water in one cup, and then drop a drop of red ink (any pigment that is easy to observe but does not change the nature of water can be used here, such as blue ink, printer color ink, but not ink and carbon ink). After mixing evenly, pour half of the colored water into another cup for comparison. Put the activated carbon into the colored water, the quantity should reach half or more of the water, so the effect will be more obvious. After standing for 10-20 minutes, compare with the contrast water sample. Under the same conditions, the stronger the decolorization effect, the better the adsorption of the activated carbon.

Look at bubbles:

When a small amount of activated carbon is put into the water, the water will gradually dip into the pore structure of the activated carbon due to the penetration of water, forcing the air in the pore to be discharged, resulting in a series of extremely small bubbles. A small bubble line will be pulled out in the water, and at the same time, the bubble sound of silk will be produced, which is very interesting. The more violent this phenomenon occurs, the longer the duration, the better the adsorption of activated carbon.