Basic principles of activated carbon

Activated carbon is a highly porous adsorbent formed by the activation of carbon materials. It has a large number of micropores and mesopores inside, providing a huge specific surface area. These pore structures make activated carbon have extremely strong physical adsorption capacity, which can effectively adsorb and remove various pollutants in the air, including volatile organic compounds (VOCs)

 

Activated carbon is a highly porous adsorbent formed by the activation of carbon materials. It has a large number of micropores and mesopores inside, providing a huge specific surface area. These pore structures make activated carbon have extremely strong physical adsorption capacity, which can effectively adsorb and remove various pollutants in the air, including volatile organic compounds (VOCs).

Definition and hazards of VOC

Volatile organic compounds (VOCs) refer to a class of organic compounds that are easily volatile at room temperature, mainly including benzene, toluene, xylene, formaldehyde, etc. VOCs are widely present in products such as building materials, furniture, paints, and detergents. Due to its volatility, VOCs can quickly enter the air and have a serious impact on indoor air quality. Long-term exposure to high concentrations of VOCs can cause headaches, nausea, allergic reactions, and even cancer.

Mechanism of activated carbon to remove VOCs

Physical adsorption:

Activated carbon can physically adsorb VOC molecules through its rich pore structure. Due to the large specific surface area of ​​activated carbon, its surface can provide a large number of adsorption sites, thereby effectively capturing and fixing VOC molecules.

Chemical adsorption:

In addition to physical adsorption, the surface of activated carbon also contains some oxygen-containing groups (such as carboxyl and hydroxyl groups), which can react chemically with certain VOC molecules, thereby further enhancing the adsorption capacity of activated carbon.  

Surface modification:

In order to improve the adsorption performance of activated carbon, scientists have modified the surface of activated carbon by various methods, such as introducing acidic or basic groups on the surface of activated carbon, or loading some metal oxides. These modification measures can significantly improve the adsorption capacity of activated carbon for specific VOCs.

Application of activated carbon Air purifier:

Many air purifiers use activated carbon filters to remove VOCs and other harmful gases from indoor air. Activated carbon filters are usually used in combination with HEPA filters to achieve dual purification of particulate matter and gaseous pollutants.  

Industrial waste gas treatment: In the process of industrial production, a large amount of VOCs are often emitted. Activated carbon adsorption towers are widely used in industrial waste gas treatment, which can effectively adsorb and remove VOCs in waste gas and reduce air pollution.  

Car air purification: The interior of cars often contains high concentrations of VOCs, especially new cars. Car air purifiers or activated carbon filters can effectively remove VOCs from the air in the car and improve air quality.  

Building materials and furniture:

Some environmentally friendly building materials and furniture will add activated carbon components during the production process to adsorb and reduce the VOCs released by the material itself, thereby improving indoor air quality.   Regeneration and treatment of activated carbon Due to the limited adsorption capacity of activated carbon, the adsorption effect will be significantly reduced when its pores are filled with pollutants. Therefore, the regeneration and treatment of activated carbon is very important.

Common regeneration methods include:  

Thermal regeneration: Desorption of VOC molecules adsorbed on the surface of activated carbon by heating, thereby restoring the adsorption capacity of activated carbon. This method is suitable for most activated carbons that have adsorbed organic matter.

Chemical regeneration:

Use specific chemical solvents to elute pollutants on the surface of activated carbon. This method is usually used for activated carbon that has adsorbed specific pollutants.  

Biological regeneration: Use microorganisms to decompose pollutants on the surface of activated carbon to achieve the regeneration of activated carbon. This method is an environmentally friendly regeneration technology, but its application needs further research and optimization.  

Future development of activated carbon technology With the enhancement of environmental awareness and the advancement of technology, activated carbon technology has broad application prospects in removing VOCs and purifying air. Future research directions include:  

Development of high-performance activated carbon materials: Through the advancement of nanotechnology and materials science, develop activated carbon materials with higher specific surface area and better pore structure to improve their adsorption capacity and service life.  

Surface modification of activated carbon: Study more efficient surface modification methods to enhance the selective adsorption capacity of activated carbon for specific VOCs. For example, develop functionalized activated carbon materials that can specifically adsorb certain difficult-to-remove VOCs.  

Activated carbon regeneration technology: Optimize existing regeneration technology, reduce energy consumption and cost during regeneration, and improve regeneration efficiency. At the same time, study environmentally friendly regeneration methods to reduce secondary pollution during regeneration.  

Comprehensive treatment technology:

Combine activated carbon technology with other air purification technologies (such as photocatalysis and plasma technology) to develop comprehensive air purification solutions to cope with complex polluted environments.  

Summary As an efficient adsorption material, activated carbon has significant advantages in removing VOCs and purifying air. Through continuous technological innovation and application promotion, activated carbon technology will play an increasingly important role in improving air quality, protecting the environment and human health.