Adsorption study of mercury on charcoal

After some of the mercury poisoning tragedies like Minamata disaster, containment of mercury pollution has become an environmental concern worldwide. Among the different approaches like cementation. ion exchange to remove inorganic mercury ion from waste waters, adsorption is a noteworthy technique due to its simplicity and cheapness. The present adsorption study is done with mercuric nitrate solution in the range of 100 to 900 mgl-t using activated charcoal powder, (E.Merck), activated coconut shell, charcoal and commercial wood charcoal. The shape of the adsorption isotherm obtained reveals multilayer theory of adsorption. Among the three carbon materials mentioned. activated coconut charcoal shows the highest degree of adsorption. At 500 mgl-t initial mercury, coconut charcoal gives 64 mg per gm of adsorbent at pH 2. Wood charcoal without specific adsorption treatment shows an adsorption of 24 mg per gm of adsorbent. Though increase of acidity decreases the adsorption capacity, a capacity of 24 mg per gm is found at 0.5 pH corresponding to 0.32 N compared to 42 mg per gm at 2 pH corresponding to 0.01 N