Activated charcoal colored compounds

Potassium Graphite. Potassium, mbidium, and cesium react with graphite and activated charcoal to form intercalation compounds CgM, C24M, C gM, C gM, and C qM (61,62). Potassium graphite [12081 -88-8] 8 P gold-colored flakes, is prepared by mixing molten potassium with graphite at 120—150°C. 

If the solution is only slightly colored, the impurities will stay in solution. Otherwise, the big gun, activated charcoal, may be needed (see Activated Charcoal ). Remember, if you were working with a colored compound, it would be silly to try to get rid of all the color, since you would get rid of all the compound and probably all your grade. 

Frequently crystals are well formed and melt sharply but have a colored impurity present. In many cases, if a solution containing the compound is boiled with a small quantity of activated charcoal, the colored impurity is adsorbed preferentially if this is unsuccessful, a pass of the solution through a short alumina column (Sec. 2.6.1) can be attempted. 

Organic compounds in particular may contain colored impurities and it is frequently possible to remove these by thoroughly mixing the original hot solution with activated charcoal before filtration and crystallization. 

The use of carbon in drinking water treatment is thought to date back more than 4000 years, as there is archaeological and written evidence that filtration through charcoal was used to improve the taste of drinking water as far back as 2000 BC. In modern times, since the 1920s, activated carbon has been used in conjunction with conventional water treatment processes to improve the esthetic quality (taste, odor, color) and to reduce the probability of potentially toxic compounds reaching the consumer [1],... 

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