Activated carbon typically requires impregnation to enhance its selective adsorption or catalytic conversion capabilities for specific pollutants.

Impregnation is a post-treatment process tailored to specific application needs. By immersing activated carbon in a solution containing specific chemicals, functional components are loaded onto the surface of its internal pores, thereby improving its purification efficiency in complex gaseous or liquid environments. This method not only preserves the original physical adsorption capacity of activated carbon but also introduces chemical adsorption and catalysis, achieving multifunctional synergistic purification.

I. Impregnation Requirements by Application Scenarios

Gas Protection and Air Purification

Gas Masks and Military Protection: To counter chemical agents (such as phosgene, cyanogen chloride, and chloroethyl ketone), activated carbon needs to be impregnated with copper salts, chromium salts, silver salts, etc., forming materials with multiple functions including physical adsorption, chemical adsorption, and catalytic decomposition. This type of impregnated activated carbon is widely used in NBC (nuclear, biological, and chemical) protection.

Industrial Waste Gas Treatment:

Removal of Hydrogen Sulfide (H₂S): Activated carbon impregnated with sodium hydroxide or alkaline solutions can effectively neutralize acidic gases.

Removal of Mercury Vapor: Activated carbon treated with iodine compounds can efficiently adsorb and fix mercury vapor, commonly used in flue gas purification in coal-fired power plants.

Elimination of Formaldehyde: Activated carbon impregnated with manganese dioxide (MnO₂) can catalytically oxidize formaldehyde to carbon dioxide and water, avoiding secondary pollution.

Adsorption of Radioactive Methyl Iodine: Iodinated activated carbon is commonly used in nuclear facilities to capture radioactive gases, ensuring environmental safety.

Drinking Water and Liquid Purification

Sterilization and Bacteriostasis: Silver-salt impregnated activated carbon releases trace amounts of silver ions, inhibiting microbial growth, suitable for household water purifiers and medical water systems.

Removal of Organic Pollutants: Activated carbon impregnated with cobalt phthalocyanine can be used to catalytically oxidize thiols in water, improving water quality stability.

Catalysis and Industrial Synthesis

Activated carbon impregnated with precious metals (such as palladium and platinum) is a common catalyst support; for example, palladium-coated activated carbon is widely used in hydrogenation reactions.

Activated carbon impregnated with alkaline solutions (such as KOH and NaOH) can enhance its performance in the adsorption of organic gases, and is particularly suitable for the adsorption and purification of oxidizing gases in PTA units.