PREPARATION AND CHARACTERIZATION OF ACTIVATED CARBONS FROM EUCALYPTUS KRAFT LIGNIN

Preparation of activated carbons from eucalyptus kraft lignin has been investigated. A pre-treatment method has been established to avoid partial fusion and swelling in the carbonization stage. Carbonization has been studied at different temperatures and the structure of the microporous chars has been characterized. Activated carbons have been prepared from CO2 partial gasification of chars obtained at 823 and 1073 K. Both chars show a comparable behavior regarding to the evolution of porous structure. Activation increases both total and narrow microporosity and develops a substantial mesoporosity. At high burnoff levels, macroporosity becomes also significant. BET surface areas in the vicinity of 1,300-1,400 m2/g have been achieved at burnoff levels around 70-75% which correspond to overall carbon to lignin yields of about 10%-11% (d.a.f. basis).