Thermodynamic study of adsorption of homologous anionic and cationic surfactants.
The simplified form of an integral adsorption isotherm based on Butler's equation was applied to describe surface behavior of a series of anionic (sodium alkylsulfonates) and cationic (alkylpyridinium halides) surfactants. This theory allows for the calculation of the free energy of adsorption (Delta G jk) value corresponding to the ability of a particular surfactant to undergo adsorption. The obtained results indicate that the value of Delta G jk depends linearly on the length of the hydrocarbon chain as well as on the kind and concentration of the added inorganic electrolyte. Moreover, it has been found that in the case of surfactants, which have the same length of the alkyl chain and adsorb from solutions containing the same inorganic electrolyte, the charge of hydrophilic group has insignificant influence on the value of Delta G jk.
Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland.
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D000327:Adsorption; D000838:Anions / Q000737:chemistry; D002412:Cations / Q000737:chemistry; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*; D013816:Thermodynamics
D000838:Anions; D002412:Cations; D013501:Surface-Active Agents