What is activated carbon? Activated carbon is a kind of black powder, granular or pellet shaped amorphous, with porous carbon, the main component is carbon, but also contains a small amount of oxygen, hydrogen, sulfur, nitrogen, chlorine. It also has the fine structure of graphite, but the grains are small and the layers are irregular.

It has a large surface area (500-1000 m2 / g) and strong adsorption performance. It can adsorb gas, liquid or colloidal solid on its surface; for gas and liquid, the mass of adsorbed material can be close to that 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 is, the lower the temperature is, the higher the adsorption capacity is. On the contrary, decompression and heating are favorable for gas desorption.

It is commonly used for gas adsorption, separation and purification, solvent recovery, decolorizing agent for sugar liquid, oil, glycerin and medicine, deodorant for drinking water and refrigerator, filter agent in gas mask, and carrier of catalyst or metal salt catalyst. In the early stage, the raw materials for the production of activated carbon were wood, hard shell or animal bone. Later, coal was mainly used to produce activated carbon after carbonization and activation.

Manufacturing method of activated carbon:

1. Chemical activated carbon, that is: carbon containing raw materials and some chemicals after heat treatment, the method of preparation of activated carbon is called chemical method. Activated carbon produced by chemical method is also called chemical activated carbon or chemical carbon.

2. Physical activated carbon is a method that takes carbon as raw material, water vapor, carbon dioxide, air (mainly oxygen) or their mixture (flue gas) as activation medium, and is activated at high temperature (600-1000 ℃). The main factors affecting the adsorption of activated carbon are as follows

1. Contact time: The contact time between activated carbon and adsorbate should be guaranteed to make the adsorption close to equilibrium and make full use of adsorption capacity.

2. Temperature: Temperature has little effect on the adsorption of activated carbon.

3. The properties of the adsorbate are as follows It depends on its solubility, surface free energy, polarity, molecular size and unsaturation of adsorbate, concentration of adsorbate, etc.

4. Coexisting substances: The adsorption capacity of activated carbon to a certain kind of adsorbent is worse than that of only containing this kind of adsorbent.

5. PH value of wastewater: Activated carbon generally has higher adsorption rate in acidic solution than in alkaline solution. The pH value will affect the state and solubility of adsorbate in water, thus affecting the adsorption effect.

6. The properties of activated carbon adsorbent are as follows The larger the surface area, the stronger the adsorption capacity; activated carbon is a non-polar molecule, easy to adsorb non-polar or very low-polarity adsorbate; the size of activated carbon adsorbent particles, pore structure and distribution and surface chemical properties also have a great impact on adsorption.