Carbon from Coconut Shells
Activated carbons are the carbons with active sites capable of adsorbing,
sometimes preferentially, many organic molecules. These active sites are
created by certain standardised procedures and treatments. It is possible
to have activated carbons with hydrophilic and lyophilic surfaces, capable
of increased adsorption of water and other polar organic vapours, and with
an acid surface suitable for removal of ammonia and other alkaline pollutants
from industrial effluents. It is also possible to impart benzophilic and
aromatic surfaces for improved benzene adsorption.
The bulk of the activated carbon is used either in liquid phase (mostly decolorisation and effluent treatment) or vapour phase (air pollution abatement, recovery and removal of organic compounds from industrial off gases.
The activated carbons are, in general, obtained by conventional two step process of carbonisation and activation. These steps are carried out either in two different units or a single unit. But it is more economical to have the carbonised near the raw material site and the activator near the market site.
Coconut shells serve as an excellent source of raw material for the manufacture of activated carbon. Since coconut shells are abundantly available in Karnataka, the feasibility of making activated carbon from coconut shells was explored.