Characteristics of Activated Carbon Purification Technology for Treating Domestic Sewage

Application of activated carbon purification technology in domestic sewage treatment

The process of activated carbon adsorbing impurities in water is quite complex, including the combined effects of ionic attraction, molecular forces (van der Waals forces) and chemical heterogeneous forces. The differences in the processing of activated carbon will also lead to differences in its adsorption force. The activated carbon adsorption method uses the porous characteristics of activated carbon to remove one or more impurities in the water by adsorbing them on the surface of the activated carbon. Such as removing organic matter, colloidal particles, microorganisms, residual chlorine, odor, etc. from water. Adsorption is composed of two rate forms: fast diffusion and slow diffusion.

Fast diffusion can exert more than 60% to 80% of the adsorption capacity within a few hours. It is the diffusion of solute molecules along the large pores with low resistance in the carbon molecular structure. In the process, when solute molecules enter the pores connected to the macropores, they encounter great resistance due to their small pore size, resulting in slow diffusion. The adsorption capacity of activated carbon is not only related to the specific surface area, but also inseparable from the pore size structure of the pores. Macropores provide diffusion channels for solute molecules to enter the fine pores to achieve adsorption. Therefore, the adsorption force for solute molecules is mainly affected by macropores. 

The organic matter contained in water includes not only small molecules, but also various macromolecules. The area occupied by pores exceeds 95% of the surface area. The amount of adsorption depends on the pores. Therefore, in the treatment process of domestic sewage, appropriate activated carbon must be selected to meet the different needs of different adsorbates. The adsorption of solute molecules is mainly due to molecular forces, that is, van der Waals forces play a key role. Different activated carbons have different pore diameters and distribution areas, so different types of activated carbon have different adsorption capabilities for different solute molecules. Physical adsorption is related to factors such as the affinity of activated carbon for solutes, the solubility of solutes, the size of solute molecules, the pore distribution of activated carbons, and surface area.

Application of activated carbon purification technology in domestic sewage treatment

1.Characteristics of activated carbon purification technology for treating domestic sewage.

There are several types of activated carbon adsorption methods, namely fixed bed, contact adsorption, moving bed and flowing bed. Among them, the adsorption method of powdered activated carbon is only contact adsorption, which is also its characteristic. In the process of treating domestic sewage problems, the dosage of powdered activated carbon is increased according to different water quality conditions. It is particularly useful for projects with large changes in sewage quality. Good results. At the same time, powdered activated carbon can also be used for dry or wet throwing according to different needs. Wet throwing can deal with some daily sewage problems, and dry throwing can be used for emergency treatment of sewage. At the same time, the carbon type of powdered activated carbon must also be determined based on the different water quality of the raw water, especially the different molecular weight distribution of organic matter contained in the water. In the emergency treatment of domestic sewage, activated carbon can be put into the raw water in front of the sedimentation tank, so that it can fully contact and adsorb. After the adsorption is saturated, it can be removed by sedimentation.

2. Application of biological activated carbon technology

Activated carbon plays an important role in domestic sewage treatment due to its excellent adsorption capacity. Its unique molecular structure and specific surface activity, resistance to strong acids and alkalis, high temperature and high pressure resistance and other comprehensive properties have attracted much attention. Widely used in domestic sewage treatment. Its status is rising day by day. However, activated carbon also has a series of problems such as easy adsorption saturation and high regeneration costs. In order to effectively solve this problem, people combined the principle of waste biodegradation with the principle of activated carbon adsorption to create biological activated carbon purification technology. Biological activated carbon purification technology includes two aspects: biodegradation and activated carbon adsorption. It not only increases the saturation of activated carbon, but also enhances its adsorption performance, so it has attracted much attention.