Generally speaking, the greater the specific surface area (BET) of coconut shell activated carbon, the greater the adsorption capacity; but sometimes it is not necessarily.https://www.powdered-activated-carbon.com/
BET is a widely used parameter for measuring the total surface area of coconut shell activated carbon by nitrogen or butane adsorption. It stands to reason that the larger the BET, the greater the adsorption force.
However, this concept has limitations in practical applications, because the pores of coconut shell activated carbon have the difference between macropores, mesopores and micropores. Sometimes only part of the pores are suitable for the entry of certain types of adsorbents, so the total surface area and Porvolume data (for example, the total surface area is usually about 450-1 80Om2/g and the pore volume is about 0.7-1.8 ml/g) cannot be used to evaluate the effectiveness of the adsorbed coconut shell activated carbon. Most of the total surface area belongs to micropores. The typical data is: micropores account for 1000m2/g, mesopores account for 10-100m2/g, and macropores account for lm2/g.
In liquid phase applications, the adsorption of organic matter generally increases with the increase in molecular weight (molecular size). Until the molecule is too large to enter the hole. Many high-molecular-weight organics, such as colored substances or humus, are excluded from the micropores. In this case, coconut shell activated carbon with more mesopores needs to be used, while microporous carbon with high total surface area is powerless.
The most ideal coconut shell activated carbon has a large number of pores just slightly larger than the adsorbate molecules. If the pore is too small, the adsorbent cannot enter; if the pore is too large, the surface area per unit volume is reduced. It is best to encounter molecules with a molecular weight between 300 and 100,000, which is equivalent to a pore size between 0.5 and 4 nm, and darker pigments are often larger molecules.
In gas phase applications, small molecules are adsorbed into human pores. At this time the concept of total surface area is applicable. For example, the recovery of solvents in the air or the prevention of gasoline escape in cars.
As for the adsorption of metal complexes by coconut shell activated carbon, it involves the formation of chemical bonds, and it is not that the larger the BET, the better. For example, from the solution of gold cyanide adsorption, the coconut shell activated carbon of the steam activation method has a high affinity for gold cyanide, while the coconut shell activated carbon of the chemical activation method has no affinity even if it is porous.https://www.granular-activated-carbon.com/
BET is a widely used parameter for measuring the total surface area of coconut shell activated carbon by nitrogen or butane adsorption. It stands to reason that the larger the BET, the greater the adsorption force.
However, this concept has limitations in practical applications, because the pores of coconut shell activated carbon have the difference between macropores, mesopores and micropores. Sometimes only part of the pores are suitable for the entry of certain types of adsorbents, so the total surface area and Porvolume data (for example, the total surface area is usually about 450-1 80Om2/g and the pore volume is about 0.7-1.8 ml/g) cannot be used to evaluate the effectiveness of the adsorbed coconut shell activated carbon. Most of the total surface area belongs to micropores. The typical data is: micropores account for 1000m2/g, mesopores account for 10-100m2/g, and macropores account for lm2/g.
In liquid phase applications, the adsorption of organic matter generally increases with the increase in molecular weight (molecular size). Until the molecule is too large to enter the hole. Many high-molecular-weight organics, such as colored substances or humus, are excluded from the micropores. In this case, coconut shell activated carbon with more mesopores needs to be used, while microporous carbon with high total surface area is powerless.
The most ideal coconut shell activated carbon has a large number of pores just slightly larger than the adsorbate molecules. If the pore is too small, the adsorbent cannot enter; if the pore is too large, the surface area per unit volume is reduced. It is best to encounter molecules with a molecular weight between 300 and 100,000, which is equivalent to a pore size between 0.5 and 4 nm, and darker pigments are often larger molecules.
In gas phase applications, small molecules are adsorbed into human pores. At this time the concept of total surface area is applicable. For example, the recovery of solvents in the air or the prevention of gasoline escape in cars.
As for the adsorption of metal complexes by coconut shell activated carbon, it involves the formation of chemical bonds, and it is not that the larger the BET, the better. For example, from the solution of gold cyanide adsorption, the coconut shell activated carbon of the steam activation method has a high affinity for gold cyanide, while the coconut shell activated carbon of the chemical activation method has no affinity even if it is porous.https://www.granular-activated-carbon.com/
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