Adsorption of lindane from water onto GAC:: effect of carbon loading on kinetic behavior

Batch kinetic experiments of adsorption of lindane in dilute aqueous solution onto F-400 granular activated carbon (GAC) with different carbon weight and initial concentration were analyzed. Concentration decay of lindane was measured by means of SPME (solid phase micro extraction). A high level of energetic and structural heterogeneity of the F-400 activated carbon was observed by means of TG analysis. An adsorption model including film-, macropore-, and micropore-diffusion based on the branched pore model was fitted to experimental data. The effect of carbon loading on model parameters can be summarized as follows: (i) the effective macropore diffusivity, including pore and surface diffusivity, and the micropore rate coefficient have little dependence on carbon loading, and (ii) the fraction of adsorptive capacity in macropores depends strongly on carbon loading, which is attributed to the difference in adsorptive affinity in macro- and micropores. (C) 2002 Elsevier Science B.V. All rights reserved.