Activation energies of phenanthrene desorption from carbonaceous materials: Column studies

Abstract

Summary Sorption/desorption kinetics of phenanthrene from two carbonaceous samples (lignite and high-volatile bituminous coal (HC)) at different temperatures was monitored using an on-line column method. Pulverized samples ( −1 and 70–71 kJ mol −1 for lignite and HC, respectively and they did not increase significantly during the leaching procedure. At the end of the experiments desorption was almost complete and only 0.2% (lignite) and 6% (HC) of the initially sorbed phenanthrene was present after the last temperature step. Fitted diffusion coefficients as well as the comparison between the apparent activation energies and sorption/desorption enthalpies obtained for the same samples from equilibrium isotherms imply that the diffusion occurred in organic matter of the lignite and in micropores of the high-volatile bituminous coal, where higher apparent activation energies are expected.