A radiotracer investigation of the adsorption of n-octanoic acid on mild steel

The adsorption of the 14C labelled anion of n-octanoic acid by mild steel was found to be essentially complete after one hour. The extent of the equilibrium adsorption varied with concentration and obeyed the Freundlich Isotherm. The anion/acid ratio was varied by adjusting the pH of a dilute solution by addition of hydrochloric acid. The adsorption of the anion was thereby shown to be approximately twice that of the acid. This could be explained by the greater availability of the lone pair electrons on the anion for donation to the metal. (author)