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were produced in this plant by the activation of peat with steam. The NORIT
company, a manufacturer in Holland, first appeared in about 1911 and became
widely known in the sugar industry [5]. The powdered activated carbons were
used at that time mainly for decolorizing solutions in the chemical and food
industries.
On an industrial scale, the process of chemical activation of sawdust with zinc
chloride was carried out for the first time in an Austrian plant at Aussing in 1914,
and also in the dye plant of Bayer in 1915 [9]. This type of activation involved
pyrolytical heating of the carbonaceous material in the presence of dehydrating
chemicals such as zinc chloride or phosphoric acid [10].
In parallel to the developments in Europe, in the United States the first activated
carbon was produced from black ash, a waste product of soda production, after it
was accidentally discovered that the ash was effective in decolorizing liquids [5].
The first commercial production of activated carbon in the United States took
place in 1913 [11]. Activated carbon in the form of PAC was used for the first time
in 1928 by Chicago meat packers for taste and odor control [12].
The use of poisonous gases in the First World War paved the way for the
development and large-scale production of granular activated carbon (GAC). These
carbons were used in gas masks for the adsorption of poisonous gases. Subse-
quently, they were used for water treatment, solvent recovery, and air purification.
After the First World War, considerable progress was made in Europe in the
manufacture of activated carbons using new raw carbonaceous materials such as
coconut and almond shells. The treatment with zinc chloride yielded activated
carbons with high mechanical strength and high adsorptive capacities for gases
and vapors. Later, in 1935-1940, pelletized carbons were produced from sawdust
by zinc chloride activation for the recovery of volatile solvents and the removal of
benzene from town gas. Nowadays, the zinc chloride process of chemical activa-
tion has been largely superseded by the use of phosphoric acid [4].
1.2
General Use of Activated Carbon
Nowadays, activated carbon finds wide application in many areas, but especially in
the environmental field. Aside from environmental pollution control, activated
carbon is mainly used in industry in various liquid and gas phase adsorptions [1].
Among liquid phase applications one can list food processing, preparation of
alcoholic beverages, decolorization of oils and fats, product purification in sugar
refining, purification of chemicals (acids, amines, gylcerin, glycol, etc.), enzyme
purification, decaffeination of coffee, gold recovery, refining of liquid fuels, pur-
ification in electroplating operations, purification in the clothing, textile, personal
care, cosmetics, and pharmaceutical industries, and applications in the chemical
and petrochemical industries. Gas phase applications include recovery of organic
solvents, removal of sulfur-containing toxic components from exhaust gases and
recovery of sulfur, biogas purification, use in gas masks, among others. Activated
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