Charcoal is generally used in water treatment Activated carbon Its surface area may not be too large, but it should have more transition pores and larger average pore diameter. Some activated carbons for liquid phase sold in Japan have the following characteristics: specific surface area of 850 to 1000m2/g, pore volume of 0.88 to 1.5ml/g, and average pore radius of 40 to 50A. Activated carbon is used for sewage treatment, which can decolour and remove harmful substances in water quality. Granular activated carbon is made of anthracite as raw material, refined and processed by advanced technology, and its appearance is black amorphous particles; It has developed pore structure, good adsorption performance, high mechanical strength and low cost; It is used for purifying toxic gas, waste gas treatment, industrial and domestic water purification, solvent recovery, etc. Activated carbon used for water treatment should have three requirements: large adsorption capacity, fast adsorption speed and good mechanical strength.

In addition to other external conditions, the adsorption capacity of activated carbon is mainly related to the specific surface area of activated carbon. With large specific surface area and a large number of micropores, more adsorbates can be adsorbed on the wall of micropores. The adsorption rate is mainly related to the particle size and the distribution of pores. The activated carbon used for water treatment requires a relatively developed transition pore (radius 20~1000A), which is conducive to the diffusion of adsorbate into micro pores. The smaller the particle size of activated carbon is, the faster the adsorption speed is, but the water head loss should be increased, generally in the range of 8~30 mesh. The mechanical wear resistance of activated carbon directly affects the service life of activated carbon.

Activated carbon is a very small carbon particle with a large surface area, and there is a finer pore in the carbon particle capillary. This capillary has a strong adsorption capacity. Due to the large surface area of carbon particles, it can fully contact with gas (impurities). When these gases (impurities) touch the capillary tube, they are adsorbed and play a purification role.

The research on the surface area of activated carbon from fruit shell is very important. The specific surface area of activated carbon can only be measured by BET method, which is true and reliable. Many instruments in China can only be measured by direct comparison method. At present, the multi-point BET method is uniformly used for specific surface area testing at home and abroad, and the specific surface area measurement standards developed at home and abroad are based on the BET test method.

Activated carbon is a microcrystalline carbon material made of carbon materials with developed internal pore structure, black appearance, strong adsorption capacity and large surface area. Moreover, activated carbon also contains many micropores that we cannot see with the naked eye, and these micropores have a great use. It is because of the good pore structure of activated carbon that it has a strong adsorption function.