Investigation of the Sorption Activity of Native Coals to Atmospheric Oxygen

The influence of a gas atmosphere during sample preparation, granulometric composition, the duration of contact with air, and the stage of metamorphism on the sorption of oxygen by coals from the atmosphere was established. It was shown that sample preparation performed in an atmosphere of air led to the primary oxidation of the outer surface of coals, which introduced an error in the subsequent determination of the rate of oxygen sorption. Fine coal fractions (0–0.2 mm) with a more developed outer surface exhibited increased oxygen absorption activity. The rate of oxygen sorption was maximal at the initial moment of the interaction of native coals with air, and it decreased with the duration of contact. The least metamorphosed hard coals of the D brand with a high concentration of reactive functional groups and a developed porous structure were characterized by the greatest chemisorption activity.