STUDY OF POLYMERIC ALUMINUM(III) HYDROXIDE SOLUTIONS FOR APPLICATION IN WASTE-WATER TREATMENT - PROPERTIES OF THE POLYMER AND OPTIMAL CONDITIONS OF PREPARATION

The optimal conditions for the preparation of polymeric aluminum(III) hydroxide species for water treatment has been described. The partially hydrolyzed aluminum(III) solutions were characterized by ultrafiltration method, ferron assay, **2**7Al n. m. r. measurements, high pressure anion exchange chromatography and precipitation of polymeric aluminum hydroxo species with sodium sulphate. The results of these tend to suggest that the polymeric aluminum(III) hydroxide species have a size between 10-20 A; these have an average residual positive charge of 0. 54, and constitute about 80% of the total aluminum in the hydrolyzed solution. They are retained by UM05 membrane. **2**7Al measurements indicate that Al//1//3O//4(OH)//2//4**7** plus ion are the predominant polymeric species in these solutions. In addition to these the hydrolyzed aluminum(III) solutions contain low proportions of monomeric aluminum hydroxo species and inert micro-crystalline aluminum hydroxide. The effect of ageing, dilution and pH on the stability and characteristics of the aluminum hydroxide polymer were also studied in detail.