Lignin-based activated carbons for adsorption of sodium dodecylbenzene sulfonate: Equilibrium and kinetic studies

The adsorption of sodium dodecylbenzene sulfonate (SDBS) from its aqueous solution at different temperatures has been studied using three activated carbons prepared in our laboratory. Lignin was used as raw material for the preparation of activated carbons (ACs). The results of the adsorption equilibrium were analyzed and fitted to the Langmuir model. Thermodynamic magnitudes were estimated as well, and their values indicated that the adsorption processes were spontaneous and exothermic. The kinetic study showed that the processes are of second apparent order related to the concentration of the vacant active centers on the surface of the activated carbons. The values of the effective internal diffusion coefficients have been calculated applying the equations developed by Crank and Vermeulen.

Graphical abstractActivated carbons from kraft lignin revealed high capacities to remove SDBS in the aqueous phase. If the hyperbolic model is suitable for the adsorbate concentration in the liquid phase, its parameters make the adsorption kinetic constant of second order related to the solid phase.Figure optionsDownload full-size imageDownload as PowerPoint slide