System of law
Activated carbon is made by activating carbonaceous materials such as wood, coal, and husk under high temperature and anoxic conditions, and has a large specific surface area (500-1700 m2/g). The activated carbon used in the water treatment process is powdered carbon and granular carbon. Powdered carbon is suspended by adsorption, while granular carbon is filtered by adsorption. Activated carbon adsorption is widely used for advanced treatment of water treatment and secondary treatment of wastewater. Its main advantage is that the degree of treatment is high and the effect is stable. The disadvantage is that the processing costs are high.
Performance
Activated carbon is made from carbonaceous materials such as wood chips, husks and lignite, which are carbonized and activated. There are two kinds of powdery (particle size of 10 to 50 microns) and granules (particle size of 0.4 to 2.4 mm). The generality is porous and the specific surface area is large. The total surface area is 500 to 1000 m2 per gram. The main performance parameters are adsorption capacity and adsorption rate. The adsorption capacity is the mass of the dissolved mass per unit weight of the activated carbon when it reaches the adsorption saturation, and is related to the raw materials, the manufacturing process and the regeneration method. The larger the adsorption capacity, the more the amount of activated carbon used. The adsorption rate refers to the mass of the dissolved mass per unit time of the activated carbon per unit time. Due to the selectivity of adsorption, the performance parameters should be determined experimentally. Granular activated carbon must have certain mechanical strength and particle size specifications.
Under the same temperature and pressure of activated carbon, the adsorption capacity of different adsorbents for certain molecules is different.
The activated carbon continuously adsorbs the solute in the water until the adsorption equilibrium, that is, the solute concentration no longer changes. At a certain temperature, when the adsorption equilibrium is reached, the relationship between the weight of the solute absorbed by the activated carbon per unit weight and the concentration of solute in the water is called the adsorption isotherm. The curve is commonly expressed by the Freundlich method: X/M=kC1/n
Where X is the dissolved mass of the activated carbon; M is the weight of the activated carbon; C is the concentration of the solute in the water when the adsorption equilibrium is reached; k and n are the constants obtained by the test.