Activated carbon is the generic term used to describe a family of carbonaceous adsorbents with a highly crystalline form and extensively developed pore structure. Activated carbon is produced under carefully controlled conditions by grinding bituminous coal, peat or coconut shells and heating them in absence of oxygen to produce activated carbon.
Activated carbon works by adsorbing organic contaminates from liquid and vapour, adsorbing them into the surface of the carbon. Adsorption takes place within the pore structure of the activated carbon, where forces attract and hold the contaminate like a magnet.
The Activation Process
There is a wide variety of production and processing techniques used in the manufacture of activated carbon, these are dependent on:
- Nature and type of raw material.
- Desired physical form of activated carbon.
- Characteristics required for the intended application.
Typical activation techniques for activated carbon include chemical and steam activation. Chemical activation is used for the activation of peat and wood based raw materials. The raw material is impregnated with a strong dehydrating agent, typically phosphoric acid or zinc chloride mixed into a paste and then heated to temperatures of 500-800°C to activate the carbon.
Chemically activated carbons generally exhibit a very open pore structure, ideal for the adsorption of large molecules. Steam activation is used for the activation of coal and coconut shell raw material, which is usually processed in a carbonised form. Activation takes place at temperatures of 800-1100°C in the presence of steam. Carbon activated in this way generally exhibits a fine pore structure, ideal for the adsorption of compounds in both liquid and vapour phase applications.
Typical Applications Vapour Phase Activated Carbon
- Solvent recovery – recovery and control of organic solvents.
- Carbon dioxide – adsorption of alcohols, amines and mercaptans.
- Waste disposal – removal of heavy metals and dioxins.
Typical Applications Liquid Phase Activated Carbon
- Potable water – removal of dissolved organics, control of taste, odour and colour.
- Soft drinks – chlorine removal and adsorption of dissolved organics.
- Brewing – removal of THM’s, phenolics and decolourisation.
- Semiconductors – TOC reduction.
- Petrochemicals – hydrocarbon removal.
Vessels for Sale or Hire
Carbis Filtration supply a standard range of adsorber vessels for both liquid and vapour phase applications, manufactured from, stainless steel, mild steel and plastic. We also custom manufacture to specific requirements. Hire units are available for long or short term hire, for both liquid and air phase applications. Carbis offer a site service for the removal and disposal of spent carbon, spent carbon is removed using high volume air conveying equipment. The spent carbon can then be dealt with in a responsible and environmentally sensitive manner. For further information on our hire vessels please click here.
Effluent Treatment Packages
Carbis Filtration also design and manufacture a range of packages for the treatment of liquid effluent waste.