FLOCCULATION OF DISPERSE SYSTEMS BY POLYFUNCTIONAL POLYMER-INORGANIC HYBRIDS

Abstract

Development of novel high-capacity multifunctional flocculants is a promising solution to selective separation of clay suspensions. Among such flocculants, polymer-inorganic hybrids are the most attractive for their excellent performance as compared with inorganic coagulants or syn-thetic polymers. Synthesis of polymer-inorganic hybrids was carried out in two stages. At the first stage, Al(OH)3sol was obtained by condensation of aluminum chloride and ammonium carbonate in the following conditions: t = 70°C, pH = 3-4, intensive stirring. In the second stage, Al(OH)3was mixed with aqueous solutions of polymers at room temperature. By changing the melting tem-perature of hybrid samples, the presence of interactionsbetween the Al3+cation and the carboxylate groups of the analyzed acrylamide copolymers were established. This paper reports synthesis and comparative efficiency analysis of systems that contain water-soluble anionic copolymers of acryla-mide and respective polyfunctional polymer-inorganic hybrids. We performed a quantitative char-acterization of concentration and structural effects of polymer flocculants on the flocculation mechanism and sludge thickening. Sludge thickening constants were determined. Higher values of thickening constants were noted in systems with additives of hybrid samples, due to the participa-tion of their macromolecules in the formation of floccules at the first stage of the sediment process, and at the stage of thickening of sediments,their deformation and compaction were revealed while maintaining a loose structure with the formation of bulk floccules. We considered the factors al-lowing to optimize flocculation of clay dispersions by polymer-inorganic hybrids in aqueous media. These novel flocculants were shown to have a good potential for applications in filtration or flota-tion processes as well as for wastewater treatment for removal of disperse impurities.