Effect of different butanols on the adsorption of sodium dodecylsulfate on alumina

The adsorption of sodium dodecylsulfate onto alumina from aqueous solutions (0.3 M NaCl) was determined in the presence of short-chain alcohols,i.e.,1-, 2-,iso-, andtert-butanol. All adsorption isotherms of the surfactant show the same trend upon the addition of the different short-chain alcohols. The isotherm reaches its saturation level at lower surfactant equilibrium concentrations than without alcohol, and the saturation adsorption density level decreases. The reason for these changes is attributed mostly to the lowering effect of butanols on the critical micelle concentration of sodium dodecylsulfate in the aqueous bulk phase, but also the competitive adsorption of the alcohols is considered.