Porosity of carbonaceous materials prepared by the carbonization of saw-dust impregnated with an aqueous solution of halide or organic acid salt

Saw-dust of Japanese cypress, which was often used as a raw material of activated carbon, impregnated with an aqueous solution of halide or organic acid salt was carbonized and the porosities of the carbonized samples were measured. When saw-dust impregnated with potassium or sodium iodide or bromide was carbonized at 800°C, chemical activation occurred and the carbonized sample had a larger specific surface area than one prepared by normal carbonization without using inorganic compounds. However, no chemical activation was found in the case of magnesium halides and other metal chlorides. In experiments using acetates, potassium caused stronger chemical activation than sodium or magnesium. It was also found that chemical activation did not occur in carbonization at 600°C and that the chemical activation occurred at a higher carbonization temperature than the melting point of the inorganic compound used. It is therefore believed that the reactivity of the inorganic compound, such as its corrosion of the carbonaceous solid, is intensified by using a higher carbonization temperature than its melting point in order to promote the chemical activation. 2014 (No. 261), 8–13.]