Activated carbons prepared from thermally and chemically treated petroleum and coal tar pitches

Petroleum and coal tar pitches have been treated thermally at 400°C and 470°C, extracted with toluene and subsequently activated with CO₂ at 900°C. With one exception, the development of the micropore widths and volumes in the resulting carbons follows the trend observed for carbons based essentially on precursors of vegetable origin. On the other hand, petroleum pitch treated at 400°C leads to an active carbon which follows the pattern observed for cokes, semi-cokes and pyrolyzed tyres. It is suggested that the difference between the two types of active carbons is due to the large amount of compounds with low molecular weight left in the petroleum pitch after thermal soaking.