Soot was produced from acetylene pyrolysis at 1100 degrees C using 50000 ppmv acetylene. At 900 and 1100 degrees C, the influence of the oxygen concentration in a range of 100-30000 ppmv was analyzed. Applying the shrinking core model with decreasing particle size and chemical reaction control, the reaction order with respect to oxygen was obtained, which turned out to be 1. Experiments at 850 and 1000 degrees C with an oxygen concentration of 500 ppmv were also done to extend the study of the temperature influence. The activation energy of the soot oxidation process was also obtained and resulted in a value of 42.8 kJ/mol. Additionally, another soot with different structural characteristics was obtained by acetylene pyrolysis at 1100 degrees C, using 5000 ppmv acetylene. Its oxidation over a range of oxygen concentrations (250-20000 ppmv) was studied. The shrinking core model with chemical reaction control was also applied, and the reaction order with respect to oxygen was obtained, again being equal to unity.