Preparation of activated carbons from bituminous coals with CO₂ activation - Influence of coal oxidation

In this study activated carbons were prepared from three Australian bituminous coals. The influence of coal oxidation on the carbonization and activation processes and the structure of the resulting activated carbons were explored. The oxidation was conducted at 200°C in O₂ for 6 hours. During the oxidation the amount of oxygen uptake decreased with the O/C atomic ratio of the raw coal. The carbonization of the oxidized coal exhibited a broader volatile evolution with respect to temperature, and the resulting char from the oxidized coal had a larger surface area. The oxidation of the coal precursors resulted in increases in the specific surface area and pore volume of the resulting activated carbons. For the carbons from the oxidized coals, the activation rate in CO₂ was higher and the structure more accessible for CO₂ penetration.