Activated Carbon
Activated carbon, also known as activated charcoal, is a form of carbon processed to have small, low-volume pores that increase the surface area available for adsorption or chemical reactions. It is typically produced from carbonaceous materials such as coconut shells, wood, coal, or peat through activation processes involving gasification at high temperatures.
Properties and Structure
- High Surface Area: Ranges from 500 to 1500 m²/g due to a porous structure containing micropores (<2 nm), mesopores (2–50 nm), and macropores (>50 nm).
- Adsorption Mechanism: Primarily relies on Van der Waals forces for physical adsorption of organic compounds, gases, and impurities.
- Chemical Inertness: Generally chemically stable but can be modified with surface functional groups to enhance specific interactions.
Production Methods
- Physical Activation: Carbonization followed by gasification with steam or carbon dioxide at 800–1000°C.
- Chemical Activation: Impregnation with chemicals like zinc chloride, phosphoric acid, or potassium hydroxide, followed by heating at lower temperatures (500–700°C).
Applications
- Water Purification: Removal of chlorine, organic contaminants, and taste/odor compounds in municipal and household filters.
- Air Filtration: Capture of volatile organic compounds (VOCs), odors, and toxic gases in industrial settings and respirators.
- Food and Beverage Industry: Decaffeination of coffee and tea, sugar decolorization, and purification of edible oils. See 2026 06 24 Decaffeination and De alcoholization Processes History a for historical context on these specific extraction methods.
- Medical Use: Treatment of drug overdoses and poisoning by adsorbing toxins in the gastrointestinal tract.
- Gold Recovery: Adsorption of gold-cyanide complexes from leaching solutions in mining operations.
Related Concepts
- Adsorption
- Carbonization
- Water Treatment
- Decaffeination