In daily life and industrial production, charcoal and activated carbon are both common carbon-containing materials. Although they are both related to “charcoal”, they have many obvious differences. A deep understanding of these differences will help us choose and use them correctly in different scenarios.
The production process is very different
The production of charcoal is relatively basic. It is usually made by placing wood in an oxygen-deficient or limited oxygen environment and pyrolyzing it at high temperature. For example, the traditional kiln burning method uses mud to build a kiln, fills it with wood, and ignites it from the kiln door or fire door to carbonize the wood in the kiln. After the volatiles escape, charcoal is left. In this process, the organic matter in the wood decomposes and gradually transforms into charcoal mainly composed of carbon, but the whole process has not undergone special activation treatment, so its internal pore structure is relatively underdeveloped.
The production of activated carbon is a step further on the basis of charcoal. It requires two key steps: carbonization and activation. First, carbon-containing raw materials (such as wood, fruit shells, coal, etc.) are carbonized to initially convert them into charcoal. Then the carbonized product is activated by physical activation (such as high-temperature steam, carbon dioxide, etc.) or chemical activation (such as using chemical reagents such as zinc chloride and phosphoric acid). This activation process can form a large number of micropores and mesopores inside the carbon, greatly increasing its specific surface area, thus giving the activated carbon super strong adsorption capacity.
Each appearance has its own characteristics
From the appearance, the color of charcoal is usually black or dark brown, and the texture is relatively brittle. It may break if you gently break it with your hands. Its surface is also relatively rough, and common forms include block, rod, granular, etc. For example, the machine-made charcoal we often use for barbecue is mostly regular rod-shaped, with a relatively smooth surface, but the overall texture is still relatively brittle.
The color of activated carbon is generally black, but its surface is usually smooth. In addition to granular and powdery forms, common forms include columnar and spherical forms. Like activated carbon used for air purification, many are granular or columnar, which is convenient for filling in filtering equipment; while activated carbon used in some fine chemical fields may be powdery to increase its contact area with the agent.
Significant difference in adsorption performance
Adsorption performance is one of the most prominent differences between charcoal and activated carbon. The adsorption performance of charcoal is relatively weak, and its pore structure is mainly composed of macropores and mesopores. These larger pores make its adsorption capacity relatively low, and it is easy to reach saturation. For example, after placing charcoal in a humid environment for a period of time, its adsorption of water will reach saturation and no longer have a significant hygroscopic effect.
Activated carbon has a very strong adsorption capacity, and its pore structure is mainly micropores. The presence of micropores makes the specific surface area of activated carbon very large, and the total surface area per gram of activated carbon can reach more than 1500 square meters. This means that activated carbon can provide more adsorption sites, has a relatively large adsorption capacity for various substances, and is not easy to reach saturation. In water treatment, activated carbon can effectively adsorb odors, pigments, heavy metal ions, etc. in water, and can continue to work for a long time until its adsorption sites are occupied in large quantities before gradually losing the adsorption effect.
Each application field has its own focus
In terms of application fields, charcoal and activated carbon also have their own different uses.
The most common use of charcoal in life is for barbecue and heating. When barbecue, the high temperature generated by the burning of charcoal can cook the food, and its unique combustion characteristics can also add a special flavor to the food. In some rural areas or outdoor environments, charcoal is also often used as a heating fuel. In addition, in the metallurgical industry, charcoal can be used as a reducing agent to help reduce metal ores; in the chemical industry, it is also a raw material for manufacturing chemical products such as carbon disulfide.
The application areas of activated carbon are mainly concentrated in the fields of environmental protection and chemical industry. In terms of air purification, activated carbon is widely used in various air purifiers, gas masks and other equipment, which can effectively absorb harmful gases, odors and particulate matter in the air and improve air quality. In the field of water treatment, activated carbon can be used for deep treatment of water plants to remove organic pollutants, residual chlorine, etc. in water; it can also be used for industrial wastewater treatment to help purify water quality and realize the recycling of water resources. In the chemical industry, activated carbon is often used as a catalyst carrier to provide a good reaction site for chemical reactions; it can also be used for solvent recovery to help separate and purify various organic compounds.
There are obvious differences between charcoal and activated carbon in terms of production process, appearance, adsorption performance and application fields. Understanding these differences allows us to accurately select the appropriate materials according to specific needs in actual use, so as to better play their roles. Whether it is the smoke and gas of charcoal in daily life or the high efficiency of activated carbon in environmental protection and industrial fields, they all show unique value in their respective fields.
