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. Here’s a detailed overview of its characteristics, production, and applications:

General Description

Physical Form:

• Appearance:Activated carbon typically appears as a black, fine powder or as granular or pelletized forms, depending on the application.
• Texture:It is generally porous and has a highly developed internal surface area.

Chemical Composition:

• Base Material:Primarily carbon, along with small amounts of hydrogen, nitrogen, sulfur, and oxygen.
• Pore Structure:Contains micro, meso, and macro pores that facilitate the adsorption process.

Production Process

Activated carbon is produced from carbonaceous source materials, such as coconut shells, peat, wood, coal, or petroleum pitch. The activation process involves two stages:

1. Carbonization:The raw material is heated to high temperatures (500-900°C) in an inert atmosphere to reduce the volatile components, leaving behind a solid char.
2. Activation:The char is activated using steam or chemicals (like phosphoric acid or zinc chloride) at high temperatures. This process develops the internal pore structure, greatly increasing the surface area.

Properties

• High Surface Area:Typically exhibits surface areas of 500–1500 m²/g, which are essential for effective adsorption.
• Adsorption Capacity:Excellent at trapping gas molecules, organic chemicals, and other substances on its surface.
• Pore Size Distribution:The size and distribution of pores can be tailored to specific needs, enhancing performance for particular applications.

Applications

• Water Purification:Used to remove contaminants and impurities, including chlorine, odors, and colors from water through chemical adsorption.
• Air Purification:Captures airborne pollutants such as volatile organic compounds (VOCs) and odors in residential and industrial settings.
• Chemical Processing:Employed in the recovery of solvents and removal of impurities from chemical streams.
• Gold Recovery:Utilized in the gold mining industry to recover gold from cyanide solutions during the gold cyanidation process.
• Medical Uses:Used to treat poisonings and overdoses in emergency clinical settings by adsorbing toxins in the gastrointestinal tract.
• Gas Storage and Delivery:Acts as a storage medium for gases due to its microporous structure.

Safety and Handling

• Handling:Avoid creating dust, which can be a respiratory irritant. Use dust control measures and personal protective equipment (PPE) such as masks and gloves.
• Storage:Should be kept in a dry, sealed container to maintain its adsorptive capacity and prevent contamination.

Environmental Impact

• Biodegradable:Not biodegradable due to its inert nature, but it is a sustainable option when sourced from renewable materials like coconut shells.
• Recycling and Regeneration:Can often be regenerated by thermal treatment or chemical methods, extending its useful life and reducing waste.

Activated carbon’s versatility and efficacy in various purification and treatment processes make it a vital component in many industrial, environmental, and medical applications. Its ability to adsorb wide varieties of compounds makes it an essential tool in addressing pollution and enhancing air and water quality.