Adsorption of hydrocarbons on water-swollen cellulose

The adsorption of four n-alkanes (n-C7 to n-C10) and of mesitylene on water-swollen cotton cellulose has been studied by gas chromatography. From the adsorption isotherms, the relative retention of the solutes and the thermodynamic functions of adsorption at zero surface coverage, it was found that the surface properties of the gel-like system were unaffected by the quantity of water between ca. 20% and 220% by weight. The adsorptive properties of the insoluble hydrocarbons on the water–cellulose phase indicated a low-energy surface which, however, differed markedly from bulk water. The London force contribution to the surface free energy of cellulose as a function of water content was also studied. Over ca. 20% by weight of water, the value of this London component remains constant at 34 mN m–1. This is significantly larger than the value of 22 mN m–1 for bulk water. Some tentative explanations for this difference are given.