The Adsorption of Negative Ions by Colloidal Suspension of Aluminum Hydroxide

The adsorption of Ferricyanide and Oxalate ions by colloidal aluminium hydroxide at concentrations below and above the coagulation values is measured. The plot of the amount adsorbed as a function of the total concentration of the electrolyte shows three characteristic breaks. The results are of the same general type as obtained by Storks in the adsorption of the Chromate ion by the same suspension. The adsorption is considered as of two types; first, a neutralization of the positive charges on the colloidal particle, followed by surface adsorption by the coagulated particle. The second break is due to a combination of the two types of adsorption