Kinetics; surface oxidation; carbon; thermogravimetry

The kinetics of oxidation of carbonaceous materials at low temperature (<300 °C) was explored by isothermal thermogravimetry. The suggested kinetic equation is based on the assumption of three reactions - creation of the oxygen surface groups, decomposition of created oxygen surface groups and carbon burn off. Truncated Sestak-Berggren kinetic model was used for mechanism description. The optimised kinetic equation has shown the good agreement between the theoretical and experimental data and enabled calculation of conditions (temperature, oxygen pressure) for effective carbon surface oxidation (maximal oxygen chemisorption). Predicted oxygen uptake at given conditions (4.0% at 226 °C in 20% O2, 4.6% at 196 °C in 50% O2 and 4.5% at 205 °C in 80% O2) was confirmed experimentally with a very good agreement. Application of developed carbon oxidation kinetics description allows predicting optimized conditions for preparation of highly surface oxidized carbonaceous materials.