Analysis of the adsorption isotherms of a non-ionic surfactant from aqueous solution onto activated carbons

The adsorption isotherms at 20 degreesC onto four activated carbons of the non-ionic surfactant Triton X-100 from aqueous solution have been studied o ver a wide concentration range. The adsorption was explained using one or a combination of two Langmuir equations, depending on the equilibrium concen tration range studied. A description of the adsorbed layer was constructed on the basis of the information obtained from the isotherms and assuming th e model of van Oss et al. for the interfacial interaction between adsorbent and adsorbate. The results indicate that there are at least two kinds of i nteractions, the first related to a direct interaction between the activate d carbon surface and adsorbate molecules, and the second mainly due to the interaction between surfactant molecules at the adsorbent-solution interfac e leading to the formation of interfacial aggregates. (C) 2001 Elsevier Sci ence Ltd. All rights reserved.