Activated carbon for domestic wastewater treatment

Its superior physical and chemical properties make it excellent in removing organic matter, heavy metals, odors and other pollutants from water. This article will elaborate on the basic characteristics of activated carbon, its application in domestic wastewater treatment, treatment effects and its regeneration technology.

 

As an efficient adsorption material, activated carbon is widely used in domestic wastewater treatment. Its superior physical and chemical properties make it excellent in removing organic matter, heavy metals, odors and other pollutants from water. This article will elaborate on the basic characteristics of activated carbon, its application in domestic wastewater treatment, treatment effects and its regeneration technology.  

1. Basic characteristics of activated carbon

Activated carbon is a porous, amorphous carbonaceous material with a specific surface area of ​​usually 500 to 1500 square meters/gram, and has good physical adsorption and chemical adsorption properties. Its pore structure includes micropores, mesopores and macropores, which can effectively capture various pollutants in water.  

High specific surface area: The high specific surface area of ​​activated carbon provides it with abundant adsorption sites, which helps to improve the removal efficiency. Porous structure: The porous structure allows pollutants in water to penetrate and be adsorbed quickly.

Chemical stability: Activated carbon has good chemical stability and is not easy to react with components in water.

2. Application of activated carbon in domestic wastewater treatment

Removal of organic matter Domestic wastewater often contains a large amount of organic matter, including detergents, grease, protein, etc. Activated carbon can effectively remove these organic substances through physical adsorption and chemical reactions.  

Physical adsorption: Organic molecules in water are adsorbed in the pores of activated carbon through van der Waals forces. The large specific surface area enables it to remove higher concentrations of organic substances in a short time.

Chemical reaction: The functional groups on the surface of activated carbon (such as hydroxyl,carboxyl, etc.) can react with organic substances to enhance the removal effect. Removal of heavy metal ions Domestic wastewater may contain heavy metal ions, such as lead, cadmium, mercury, etc. These heavy metals are harmful to the environment and human health. Activated carbon removes these heavy metals through adsorption and complexation reactions.  

Adsorption mechanism: Heavy metal ions are captured by activated carbon through electrostatic adsorption, hydrogen bonding, etc.

Complexation reaction: The active groups on the surface of activated carbon form complexes with heavy metal ions to achieve removal. Removal of odor and color Domestic wastewater is often accompanied by odor and color problems, and activated carbon can effectively remove these odors and color.

Odor removal: Activated carbon removes volatile organic matter and other odorous substances in water through physical adsorption.

Chroma removal: The chromatic substances in water are mainly organic dyes, and activated carbon can effectively adsorb these dyes and reduce the chroma of water.

3. Treatment effect evaluation

The effect evaluation of activated carbon in domestic wastewater treatment mainly includes the following aspects:  

Adsorption capacity The adsorption capacity of activated carbon is a key indicator for evaluating its effectiveness in domestic wastewater treatment. Experiments can be used to determine the adsorption capacity of different types of activated carbon for specific pollutants. Generally speaking, the adsorption capacity of activated carbon is affected by the following factors:  

Contaminant concentration: The higher the initial pollutant concentration, the faster theadsorption rate of activated carbon is, but when saturation is reached, the adsorption capacity decreases.

Contact time: As the contact time increases, the removal rate of activated carbon for pollutants will increase, but after reaching equilibrium, the adsorption amount will tend to stabilize. Temperature: Changes in temperature will affect the adsorption characteristics of activated carbon, and usually at moderate temperatures, its adsorption effect is best.

Removal rate The removal rate is an important parameter for measuring the effect of activated carbon in practical applications. Under normal circumstances, the removal rate of activated carbon for organic matter can reach more than 80%, and the removal rate of heavy metal ions and odor substances is also relatively high.  

Treatment cost The application cost of activated carbon is closely related to its preparation, use and regeneration. When evaluating the economic feasibility of using activated carbon to treat domestic wastewater, factors such as the purchase cost of activated carbon, the amount of activated carbon added during the treatment process and the cost of later regeneration need to be considered.

4. Regeneration technology of activated carbon

Activated carbon will gradually become saturated during use, so regeneration technology is particularly important. The choice of regeneration technology not only affects the service life of activated carbon, but also affects the economy and environmental protection of wastewater treatment.

Thermal regeneration Thermal regeneration is to heat saturated activated carbon to a high temperature to remove adsorbed pollutants. The advantage of thermal regeneration is that it can effectively restore the adsorption performance of activated carbon, but it also has the problem of high energy consumption and possible damage to the structure of activated carbon.  

Chemical regeneration Chemical regeneration uses acid, alkali or other chemical reagents to treat activated carbon to desorb adsorbed pollutants. This method has a high regeneration efficiency, but it is necessary to control the use of chemical agents to prevent secondary pollution.  

Microwave regeneration Microwave regeneration is to use microwave energy to heat activated carbon and quickly desorb adsorbed pollutants. This method has a rapid reaction and relatively low energy consumption, but the equipment investment is high.

  Activated carbon has become an important treatment material in domestic wastewater treatment due to its excellent adsorption performance. By removing organic matter, heavy metals, odor and color from water, activated carbon not only improves water quality but also protects the environment. Although the application of activated carbon still faces challenges such as cost and regeneration, with the continuous advancement of technology, its application prospects in wastewater treatment are still broad. In the future, through the improvement of material modification, technology integration and monitoring technology, activated carbon will serve the environmental protection cause more effectively and contribute to the realization of sustainable development.