Activated carbon material is amorphous carbon obtained through processing, has a large specific surface area, and has good adsorption capacity for gases, inorganic or organic substances in solution, and colloidal particles. As an adsorbent with excellent performance, activated carbon material is mainly determined by its unique adsorption surface structure characteristics and surface chemical properties. Activated carbon material has stable chemical properties, high mechanical strength, acid resistance, alkali resistance, heat resistance, insoluble in water and organic solvents, can be recycled, and has been widely used in chemical industry, environmental protection, food processing, metallurgy, drug refining, military chemical protection and other fields. At present, modified activated carbon materials are widely used in the fields of sewage treatment, air pollution prevention and control, etc., and their attractive prospects are increasingly shown in the control of environmental pollution.
More than 80%-90% of activated carbon is composed of carbon elements, which is why activated carbon is a hydrophobic adsorbent. In addition to carbon, it also contains two types of admixtures: one is chemically combined elements, mainly oxygen and hydrogen, which are left in the carbon due to incomplete carbonization, or in the activation process, foreign non- The carbon element is chemically combined with the surface of activated carbon. For example, when activated with water vapor, the surface of activated carbon is oxidized or oxidized by water vapor; another type of admixture is ash, which is the inorganic part of activated carbon.
The main raw materials of activated carbon can be almost all carbon-rich organic materials, such as coal, wood, fruit shells, coconut shells, walnut shells, apricot shells, date shells, etc. These carbonaceous materials are converted into activated carbon by pyrolysis under high temperature and pressure in an activation furnace. During this activation process, a huge surface area and a complex pore structure are gradually formed, and the so-called adsorption process is carried out in these pores and on the surface. The size of the pores in activated carbon has a selective adsorption effect on the adsorbate, which is Because macromolecules cannot enter the pores of activated carbon smaller than its pores. Activated carbon is a hydrophobic adsorbent prepared by high-
temperature carbonization and activation from carbon-containing substances as raw materials. Activated carbon contains a large number of micropores and has a huge surface area, which can effectively remove color and odor, and can remove most of the organic pollutants and some inorganic substances in the secondary effluent, including some toxic heavy metals. It can effectively Remove harmful substances in water and air and improve environmental quality. However, activated carbon gradually loses its adsorption capacity during use and needs to be replaced or disposed of regularly. Activated carbon regeneration refers to the process of restoring the adsorption performance of used activated carbon through physical or chemical methods, which can save resources, reduce waste, reduce costs, and protect the environment.
The main methods of activated carbon regeneration are as follows:
- Thermal regeneration: heating the used activated carbon to a high temperature (300-800°C) to decompose or volatilize the adsorbed substances on its surface, thereby restoring its adsorption capacity. This method is suitable for situations where the adsorbed substances are easy to decompose or volatilize, such as organic solvents, chlorides, sulfides, etc. The advantages of thermal regeneration are high efficiency and simple operation, but the disadvantage is that it consumes a lot of energy, which may lead to changes in the structure and performance of activated carbon.
- Steam regeneration: The used activated carbon is brought into contact with high-temperature and high-pressure steam, so that the adsorbed substances on the surface
are taken away by the steam, thereby restoring its adsorption capacity. This method is suitable for situations where the adsorbed substances are not easy to decompose or
volatilize, such as heavy metals, dyes, pesticides, etc. The advantage of steam regeneration is that it can recover some valuable adsorbed substances, but the disadvantage is that it consumes a lot of water and may cause secondary pollution.
- Chemical regeneration: Soak the used activated carbon in an appropriate chemical
reagent to dissolve or transform the adsorbed substances on its surface, thereby restoring its adsorption capacity. This method is suitable for situations where the adsorbed substances are difficult to decompose or volatilize, such as phenols, phenolic resins, etc. The advantage of chemical regeneration is that it can increase the service life of activated carbon, but the disadvantage is that it consumes a lot of chemical reagents and may produce toxic and harmful waste liquid.