The differences between common activated carbon and modified activated carbon

The preparation method of common activated carbon
It is prepared by physical or chemical activation methods. Raw materials such as wood, coconut shells, and coal are carbonized and activated to form a porous structure.
The preparation method of common activated carbon mainly includes four steps: raw material selection, carbonization, activation and post-treatment. First, select carbon-rich raw materials such as wood, coconut shells, coal or fruit shells, etc. These raw materials need to be crushed and sieved to obtain the appropriate particle size. Then, the raw materials are carbonized at high temperatures, usually in an inert gas environment of 500-800℃, to remove volatile substances and form the initial carbonized material. After carbonization, the material undergoes an activation process. The main activation methods include physical activation and chemical activation. Physical activation involves introducing water vapor or carbon dioxide at high temperatures (800-1000℃) to form a pore structure on the surface of the carbonized material. Chemical activation involves adding chemical reagents (such as phosphoric acid, potassium hydroxide, etc.) before carbonization and conducting the reaction at a relatively low temperature to generate pores. Finally, the activated carbon needs to undergo post-treatment steps such as cooling, washing, drying and screening to remove residual chemicals and adjust the particle size, ultimately obtaining an activated carbon product with a high specific surface area and rich pore structure.
Preparation method of modified activated carbon
The preparation method of modified activated carbon is based on ordinary activated carbon and further optimizes its surface properties and pore structure through physical, chemical or biological means to enhance its adsorption performance or endow it with specific functions. Common modification methods include acid-base treatment, loading metal oxides or introducing functional groups, etc. For instance, when activated carbon is immersed in solutions such as nitric acid, sulfuric acid or sodium hydroxide, functional groups like carboxyl and hydroxyl groups are introduced to its surface through chemical reactions, thereby enhancing its adsorption capacity for specific pollutants. In addition, activated carbon can be combined with metal salt solutions (such as iron, copper, silver, etc.) through the impregnation method. After high-temperature calcination, metal oxide-supported activated carbon is formed, which is used for catalytic or antibacterial purposes. The modified activated carbon needs to go through post-treatment steps such as washing and drying to finally obtain functionalized activated carbon materials with specific properties.