Resumen
Porosity variation of activated carbons, prepared under different activation times and CO2 flows, is provided. Cellulose fibers of Eucalyptus saligna (Myrtaceae) wood were first pyrolysed in N2 with a heating rate of 5ºC min-1 , up to 800ºC. Samples were then activated at 850ºC, in CO2 flows of 15 to 120 mL min-1, during 1, 2 and 3 hours. Porosity of carbons was characterized by determining the burn-off grades of activated cellulose fibers, the specific surface areas SBET of the pores, the average radius of gyration of micropores Rg and the meso/macropores K/Q0 Porod relations. Concomitant increase of CO2 flow and activation time induced burn-off increase and micropores Rg reduction. However, improvement of SBET areas allows the authors to conclude that smaller size micropores were created in larger amounts. Under the same conditions, increases of K/Q0 indicated a sensitive creation of macropores and/or the mesopores coalescence