The production process of wood activated carbon mainly includes the following steps:
Raw material selection: The raw materials of wood activated carbon are mainly wood materials such as wood and bamboo. These raw materials need to undergo pretreatment steps such as crushing, screening and drying to remove impurities and adjust the moisture content.
Carbonization: Carbonization is one of the key steps in the manufacture of activated carbon. The pretreated wood raw materials are placed in a carbonization furnace and heated under conditions of air isolation or limited oxygen supply, and the temperature is controlled between 400°C and 600°C. As the temperature rises, the non-carbon elements in the raw materials are removed in the form of gas to form a carbon-rich solid product-carbonized material. During the carbonization process, the water in the raw materials evaporates, the volatile organic matter decomposes and escapes, and a porous structure is gradually formed.
Activation: Activation is a key process in the formation of the porous structure of activated carbon. The pores of the carbonized material are further opened by physical or chemical methods to increase the specific surface area and pore volume. Common activation methods include steam activation and chemical activation:
Steam activation : At high temperature, water vapor reacts with carbonized materials to generate gases such as hydrogen and carbon monoxide. The escape of these gases promotes the expansion and connection of the internal pores of the carbonized materials, forming a rich microporous and mesoporous structure.
Chemical activation : After mixing chemical reagents (such as phosphoric acid and zinc chloride) with the raw materials, carbonization and activation treatment are carried out. The chemical reagents decompose during the carbonization process, and the generated gases and acidic environment contribute to the formation and expansion of pores.
Post-treatment : The activated product needs to undergo post-treatment steps such as washing, drying, and screening to remove residual activators, impurities and fine powders, and adjust the particle size and appearance of the product. During the washing process, it can be rinsed with clean water or dilute acid solution multiple times to ensure that the product is pure and pollution-free.
Crushing and sieving : Finally, the treated activated carbon is crushed and sieved to obtain the final product.
Application areas of wood activated carbon : Wood activated carbon is suitable for food decolorization and air purification due to its developed pore structure. Its excellent adsorption properties make it widely used in water treatment, air purification, food processing and other fields.