Effect of Nonionic Surface-Active Agents on the Stability and Coagulation of Ferric Hydroxide Sol

摘要

This paper reports recent findings in our continuing investigation on the preparation of stable dispersions in the presence of relatively high concentrations of electrolytes. Typical practical examples of such dispersions are those prepared with ocean water as the liquid phase. The effect of twenty nonionic surfactants on the aggregative stability of a colloidal dispersion of ferric hydroxide was investigated. This ionically stabilized sol was chosen for the intermediate hydrophobic/hydrophilic character of its particles. The obtained results were essentially different from those of previous studies on the effect of nonionic surfactants on ionically stabilized sols with really hydrophobic colloidal particles. Many of the surfactants produced coagulation with no added electrolyte and with no reversal of electric charge of colloidal particles. A qualitative model is proposed to explain the observed results which is based on the way the surfactant is adsorbed on the surface of the ferric hydroxide particles. Keywords: colloidal Stability, Coagulation, Solvation Stabilization, Adsorption, Surfactants.