| abstract |
A dry flocculant powder comprises an inorganic substrate consisting essentially of metal oxide/hydroxide particles having an average particle size of less than about 30 microns, said substrate having a cationic or anionic polyelectrolyte coated onto its outer surface, preferably under other than high shear conditions. A method for coating or adhering polyelectrolytes to the outermost surface of inorganic particles comprises dispersing a polyelectrolyte in a substantially non-aqueous solvent, preferably having a low boiling point and a low to intermediate polarity relative to the polyelectrolyte; adding the inorganic particles to the solvent to form a slurry; mixing the slurry under low to moderate shear conditions; and removing excess solvent from the slurry. There is also disclosed a method for removing clay, clay-like materials, humic acids, yeast, biological cells and/or other cell debris from an aqueous stream through contact with the aforementioned dry flocculant powder. |