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NAS/CWTC 001-82 Name: ALUMINUM SULFATE, ALUM CAS No.: 10043-01-3 Chemical Formula: Description: A12(SO4)3 14 H2O Formula Weight: 546.1 A white solid in the form of powder, crystals, or plate- lettes, or as a liquid. The most common degree of hydra- tion is A12(SO4)3 14 H2O. m e commerical standard for water soluble alum is not less than 17.0% A12O3 for solid and not less than 8.0% A12O3 for liquid alum. Use: Used as a coagulant and precipitant for phosphate. Purity Requirements: The RMIC values are based on a maximum dosage of 150 mg aluminum sulfate*/liter of water and are to be compared to impurity concentrations obtained by using sample procedures described in this monograph. If the actual dosage is other than 150 mg/liter, the user is cautioned to consult Table 2 for appropriate RMIC values. RMIC mg Impurity/kg Impurity Aluminum Sulfate* Arsenic Cadmium Chromium Lead Mercury Selenium Silver 30 7 30 30 1 7 30 *Calculated on the basis of AL2(SO4)3 14 H2O 9
10 Bulk Sample Collection: Sample in accordance with Standard for Aluminum Sulfate, AWWA B403-82, American Water Works Association, Denver, Colorado (1982). Analytical Sample Preparation: In preparing samples, use acid-washed glassware and make all dilutions with deionized distilled water. Weigh 1.5 g of aluminum sulfate (dry weight basis), dissolve, and make up to 1 liter in a volumetric flask. Transfer the solution to a 15-liter beaker; add 1 N NaOH dropwise with constant stirring to adjust to pH 6. Mix well, let stand for 1 hour, and filter through a GF/C filter (or equiva- lent) with vacuum. Quantitatively transfer filtrate into a beaker, adjust to pH 2 or less with concentrated HNO3, and evaporate on a hot plate, without boiling, to reduce the volume to less than 1 liter. Cool, quantitatively transfer to a 1-liter volumetric flask, and make up to volume. Similarly, treat a reagent blank. Sample Analyses: The analyses are to be performed on the aluminum sulfate sample in accordance with: Standard Methods for the Examination of Water and Waste water, 15th Edition, American Public Health Association Washington, D.C. (1981). Arsenic Cadmium Chromium Lead Mercury Selenium Silver Section 304 Section 304 Section 304 Section 304 Section 303F Section 304 Section 304