There are many kinds of technical performance indicators of activated carbon. According to the performance represented by the indicators, these indicators are roughly divided into the following three categories：

1．Indicators indicating the size of the adsorption capacity (1) Specific surface area: The specific surface area refers to the total surface area of activated carbon per unit mass, which is the sum of the outer surface area and the inner surface area.Generally, the surface area of the adsorbent is mainly the inner surface area.(2) Iodine value: Iodine value refers to the amount of iodine adsorbed by activated carbon in a certain concentration of aqueous solution.The iodine adsorption value is used to indicate the adsorption capacity of activated carbon on liquid substances.(3) Carbon tetrachloride value (CTC): The carbon tetrachloride value is an indicator of the total pore capacity, which is measured by a saturated CCl4 air flow at zero degrees Celsius through a carbon bed at 25℃.(4) Butane value: Butane value is the amount of butane adsorbed by activated carbon per unit mass after saturated air and butane pass through the carbon bed at a specific temperature and pressure.The butane value is an important index for selecting coal-based granular activated carbon.

2．Indicators indicating special purposes (1) Methylene blue value: The methylene blue value refers to the number of milligrams of methylene blue adsorbed when the 1.0g activated carbon and the 1.0mg/L concentration of methylene blue solution reach equilibrium.The adsorption value of methylene blue is used to indicate the decolorization ability of activated carbon, and it is mostly used to indicate the decolorization ability of powdered activated carbon to liquids.(2) Molasses value: Molasses value is a method for measuring the relative decolorization ability of activated carbon in boiling molasses solution.

3．Indicators that represent the physical properties of activated carbon (1) Bulk density: Bulk density is a method of measuring the quality of a specific amount of carbon.This value is obtained by gradually adding activated carbon to a graded barrel to 100mL and measuring its quality.This value is used to calculate the amount of activated carbon required to fill a particular adsorption device (2) True density: that is, particle density, particle density is the mass of granular carbon per unit volume, excluding particles and the space between cracks greater than 0.1mm.The particle density is measured by mercury displacement.(3) Hardness: Hardness is an indicator for measuring the mechanical strength of activated carbon.After the carbon comes into contact with the steel ball, the hardness value is calculated by using the mass of the carbon on the sieve.(4) Wear value: The wear value is an indicator for measuring the wear resistance of activated carbon.The wear value of granular activated carbon indicates that granular activated carbon reduces the resistance of particles during treatment.(5) Ash content: Activated carbon contains inorganic substances, usually aluminum and silicon.The ash is the remaining residue of carbon ground into a powder that burns for 3h at 954℃.Ash is a component of activated carbon mineral oxides.(6) Moisture: Moisture is used to measure how much carbon contains water.The water content of activated carbon can also be measured by the change in the quality of activated carbon after drying at 150℃ for 3h.Moisture is the mass fraction of water adsorbed in activated carbon.