Environmental awareness has also shaped the manufacturing of activated carbons by introducing the concept that normal everyday waste materials, such as agricultural by-products are potential precursor sources of activated carbon. Nowadays, the sources of activated carbon are extensive and are ever expanding. Any low-cost material with a high carbon content and low in inorganics content can be used as precursors to produce activated carbon.

Activated carbon is the most widely used adsorbent because of its low cost, exceptionally high porosity, tuneable pore size and high adsorptive capacities . The raw materials widely used initially for the production of commercial activated carbon are coal, bone char, peat, petroleum coke, lignite, wood, coconut shells, wood charcoal, coconut shell charcoal and other biomass sources.

However, today the range of precursor materials is diverse and widespread. Nearly all organic materials with relatively high carbon content may serve as raw materials, ranging from conventional materials such as wood, coconut shell or coal to natural or synthetic polymers. 

For commercial grade carbons, the values of surface areas typically vary in the range between 500 and 1500 m2/g or even as high as 3000 m2/g. They can be further separated into two sub-categories in accordance with their applications, namely, gas phase and liquid phase, in which the former is usually microporous (pore diameter < 2 nm) in granular form (2.36–0.833 mm, or 8/20 in mesh size) and the latter is mesoporous (pore diameter lies between 2 and 50 nm) in powdered form (0.150–0.043 mm, or 100/325). 

Both granular and powdered activated carbons have been shown to be effective in wastewater treatment in which activated carbons play an important role in decolorising, odour removal, gas removal, and metal removal and recovery as well as organics adsorption.