Soft X-Ray Spectromicroscopy Investigation of the Interaction of Aquatic Humic Acid and Clay Colloids

Sub-micrometer-sized anionic polystyrene latices have been coated with uniform layers of iron compounds by aging, at elevated temperature, dispersions of the polymer colloid in the presence of aqueous solutions of ferric chloride, urea, hydrochloric acid, and polyvinylpyrrolidone. The thickness of the deposited layers could be altered by suitable adjustment of the reactant concentrations, and they could also be increased by further aging of the coated particles in the presence of aqueous solutions of ferric chloride. Hollow colloidal spheres of iron compounds were obtained by calcination of the so-coated polystyrene latices at elevated temperature in air. Different chemical compositions of hollow colloidal spheres were obtained by heating them in hydrogen. Copyright 2000 Academic Press.