Siberian Federal University

The influence of the method of thermal-alkaline activation of biochars from larch bark with NaOH on the formation of the porous structure of active carbons was established. A comparison was made of the textural characteristics and sorption properties of the active carbon samples obtained by thermal-alkaline activation of the original and carbonized larch bark. The possibility of regulation of the textural, morphological and sorption properties of active carbons by varying the method of thermal alkaline activation of the bark is shown. The most effective development of the porous structure of active carbons was observed after thermal-alkaline activation (800 °C, 20 % NaOH) of larch bark subjected to carbonization at temperatures 400 °C and 600 °C. The specific surface area of these samples reaches to 546 m2/g and 501 m2/g, respectively. Active carbons obtained by thermal-alkaline activation (800 °C, 10 % and 20 % NaOH) of the original bark have less developed specific surface area (260 and 380 m2/g, respectively). Pre-carbonization of the bark also helps to increase more than double the yield of active carbons (61.3–83.2 % wt.) compared their yield from non-carbonized bark (29.6–32.4 % wt.). The best adsorption capacity in relation to benzene (350 mg/g) is demonstrated by a sample of active carbon obtained by thermal-alkaline activation of bark, pre-carbonized at 400 °C, and in terms of methylene blue sorption (94 mg/g) – by a sample obtained from bark pre-carbonized at 600 °C