Sorption phenomena of methanol on air oxidized Taiheiyo coal were investigated by repeated uptake and desorption experiments. Change in the heat of sorption on the oxidized coal during the repeated procedure was similar to that on unoxidized coal only heat treated. Heat of sorption was higher for the oxidized coal than the unoxidized coal. It was suggested that certain sites strongly interact with methanol in the unoxidized coal were not physical structures but were chemical structure, mainly oxygen containing functional groups. By comparing isotherms and heat of sorption of the oxidized coal before and after reheat treatment, it was presumed that the sites had stronger interaction with methanol in the oxidized coal than in the unoxidized coal. Oxygen containing functional groups introduced by the oxidation might act as the sites which strongly interact with methanol.
