Activated Carbon ── Enemy of Pollutants. Introduction. Activated carbon is the trade name for highly porous product It can be made from wood, peat, coconut shells and even PVC. Activated carbon has a wide range of uses, such as: 1 Adsorbent in gas- and liquid-phases
Activated Carbon ── Enemy of Pollutants
1 Adsorbent in gas- and liquid-phases
2.Purifier for gases and solutions
4.Treating waste water
We should consider the following requirements
Carbonisation can ensure that the carbonaceous materials to have the following features that meet the requirements of activation
The International Union of Pure and Applied Chemistry (IUPAC) classifies the porosities as follows:
Effective Radii (nm)
1 – 25
Volume of the Pores (cm3g-1)
0.2 – 0.8
0.1 – 0.5
0.2 – 0.6
Specific surface areas (m2g-1)
20 – 100
200 – 450
Entrance of AC and act as transport arteries
Contribution to adsorption and transport arteries
The adsorption process mainly depends on the following factors:
1)Physical properties of the activated carbon, such as pore size distribution and surface area;
2)The chemical nature of the carbon source, or the amount of oxygen and hydrogen associated with it;
3)Chemical composition and concentration of the compounds;
4)The temperature and pH of the water; and
5)The flow rate or time exposure of water to activated carbon.
6)Moisture content, apparent density, hardness and etc.
Adsorption is caused by London Dispersion Forces, a type of Van der Waals Force which exists between molecules.
London Dispersion Forces are extremely short ranged and sensitive to the distance between the carbon surface and the adsorbate molecule.
> Adsorption for gas phase
> Adsorption on liquid phase
Activated carbon used for the removal from blood not only externally introduced poisons but also of toxins which appear in the blood due to the failure of the patient’s kidneys.
1.Thermal and gas methods
2.Extraction and chemical methods
3.Electric and Electrochemical methods
Only granular active carbons were subjected to regeneration since they are much more expensive.
It is possible to avoid losses of the activated carbon during transportation are extraction with special solvents.
The disadvantage of such processes is the need to use large volumes of solvent for complete desorption.
This methods reduces significantly the costs of regeneration. As with chemical and extraction methods, the electrochemical methods are very selective with respect to the adsorbates to be removed from the carbon surface.
Vacuum regeneration is often used either in conjunction with other methods. The advantage of the vacuum method is that the adsorbent does not react chemically during the regeneration, nor is diluted with regeneration agents.
Biological regeneration of waste waters consists of the symbiotic action of aerobic and anaerobic bacteria