The adsorption of linear alkyl sulphates, (AS, C8 to C14 homologues) on two river sediments was measured at 25°C in 0.01 M NaHCO3at pH 7.6. The results were compared with the adsorption of linear alkylbenzene sulphonates, LAS, (C10 to C13 homologue mixture) on the same sediments under identical conditions. Both AS and LAS exhibited fast adsorption phases ( <20 min), with the AS demonstrating an additional slow disappearance from the solution over several hours. Extensive oxidative treatment of the sediment greatly reduced the adsorption capacity for AS and altered the kinetics. Henry's law adsorption constants (partition coefficients) were evaluated for each of the homologues in each surfactant series. The results are interpreted in terms of a hydrophobic bonding mechanism. The increase in the free energy of adsorption for the addition of successive methylene groups to the alkyl chain were estimated as 1.13 and 3.80 kJ mol-1for AS and LAS, respectively. © 1991.
Marchesi, J. R., House, W. A., White, G. F., Russell, N. J., & Farr, I. S. (1991). A comparative study of the adsorption of linear alkyl sulphates and alkylbenzene sulphonates on river sediments. Colloids and Surfaces, 53(1), 63–78. https://doi.org/10.1016/0166-6622(91)80036-N