Granular Activated Carbon
Municipal Water Supply
Published Online: 15 JUL 2005
Copyright © 2005 by John Wiley & Sons, Inc.
How to Cite
Mohan, D. and Singh, K. P. 2005. Granular Activated Carbon. Water Encyclopedia. 1:92–107.
- Published Online: 15 JUL 2005
Activated carbon is the generic term used to describe a family of carbonaceous adsorbents with a highly crystalline form and extensively developed internal pore structure. Activated carbon is distinguished from elemental carbon by the removal of all noncarbon impurities and the oxidation of the carbon surface. Activated carbon has the highest volume of adsorbing porosity of any substance known to humans (5 grams of activated carbon can have the surface area of a football field). It can be defined as:
Activated carbon is a crude form of graphite, with a random or amorphous structure, which is highly porous, over a broad range of pore sizes, from visible cracks and crevices, to cracks and crevices of molecular dimensions.
The use of activated carbon is not new. The Egyptians used carbonized wood around 1500 b.c. as an adsorbent for medicinal purposes as well as a purifying agent. The ancient Hindus in India used charcoal for filtration of drinking water. However, the basis for industrial production of active carbons was established in 1900–1901 in order to replace bone char in the sugar refining process.
Active carbons can be prepared from a wide range of carbonaceous materials, which include coconut shells, wood char, lignin, petroleum coke, bone char, peat, saw dust, carbon black, rice hulls, sugar, peach pits, fish, fertilizer waste, and waste rubber tire. The range of raw materials is diverse and widespread and greatly influenced by the need to produce low-cost carbon. Among the most commonly used raw materials, precursors for the production of commercially activated carbons are wood (130,000 tons/year), coal (100,000 tons/year), lignite (50,000 tons/year), coconut shell (35,000 tons/year), and peat (35,000 tons/year).
- activated carbon;
- carbonaceous adsorbents;
- adsorbing porosity;
- carbonized wood;
- spherical activated carbon;
- impregnated activated carbon;
- polymer coated activated carbons;
- physical or thermal activation;
- adsorption equilibrium;
- moving bed system;