1. Based on Source Material:

• Coal-based Activated Carbon: Derived from coal, including bituminous, sub-bituminous, and anthracite coal.

• Wood-based Activated Carbon: Made from wood, including sawdust, wood chips, and other wood by-products.

• Coconut Shell-based Activated Carbon: Produced from coconut shells, known for its high microporosity and hardness.

• Peat-based Activated Carbon: Derived from peat, a natural organic material.

• Other Biomass-based Activated Carbon: Made from other organic materials like fruit pits, nut shells, and agricultural waste.

2. Based on Physical Form:

• Powdered Activated Carbon (PAC): Fine particles with a diameter of less than 0.18 mm. It is typically used in liquid-phase applications and for emergency water treatment.

• Granular Activated Carbon (GAC): Larger particles with a diameter ranging from 0.2 to 5 mm. It is commonly used in water filtration systems and gas-phase applications.

• Pelletized Activated Carbon: Cylindrical pellets with a diameter of 0.8 to 5 mm. It is used in gas-phase applications due to its low pressure drop and high mechanical strength.

• Extruded Activated Carbon: Cylindrical or block-shaped carbon with a diameter of 1 to 5 mm. It is used in gas-phase applications and for solvent recovery.

• Spherical Activated Carbon: Spherical particles with a diameter of 0.35 to 0.80 mm. It is used in specialized applications like blood purification.

3. Based on Activation Method:

• Physical Activation: Involves carbonization of the raw material followed by activation using gases like steam, carbon dioxide, or air at high temperatures (600-1200°C).

• Chemical Activation: Involves impregnation of the raw material with chemicals like phosphoric acid, potassium hydroxide, or zinc chloride, followed by carbonization at lower temperatures (400-800°C).

4. Based on Pore Size:

• Microporous Activated Carbon: Pores are less than 2 nm in diameter. It is suitable for adsorbing small molecules and is commonly used in gas-phase applications.

• Mesoporous Activated Carbon: Pores are between 2 and 50 nm in diameter. It is used for adsorbing larger molecules and in liquid-phase applications.

• Macroporous Activated Carbon: Pores are greater than 50 nm in diameter. It is used for adsorbing very large molecules and in applications requiring rapid adsorption.

5. Based on Application:

• Water Treatment: Used for removing contaminants, organic compounds, and chlorine from water.

• Air Purification: Used for capturing volatile organic compounds (VOCs), odors, and other airborne pollutants.

• Food and Beverage Industry: Used for decolorization, deodorization, and purification of food products and beverages.

• Medical and Pharmaceutical: Used in medical treatments like poison antidotes and in pharmaceutical manufacturing for purification.

• Industrial Processes: Used in solvent recovery, gold extraction, and chemical purification.

6. Based on Surface Chemistry:

• Hydrophobic Activated Carbon: Has a non-polar surface, making it suitable for adsorbing non-polar substances like organic compounds.

• Hydrophilic Activated Carbon: Has a polar surface, making it suitable for adsorbing polar substances like water vapor and certain gases.

Each type of activated carbon has specific properties that make it suitable for particular applications. The choice of activated carbon depends on factors like the nature of the contaminants, the phase of the medium (liquid or gas), and the required adsorption capacity.