THE INVESTIGATION OF ALUMINUM SPECIATION IN NATURAL AND POTABLE WATERS USING SHORT-COLUMN ION CHROMATOGRAPHY

A highly sensitive and selective short-column ion chromatography method for the direct investigation of aluminium species in water samples is presented. Studies with pure aluminium standards indicated that aluminium species of general formula Al(OH)t (3-x) +, where x can have values from 1 to 4 depending on pH, gave a single peak, and the presence of fluoride or organic complexing acids gave additional peaks close to the solvent front. Once formed the aluminium fluoro species were stable enough to be chromatographed without significant decomposition. Reservoir and drinking water samples were analyzed by this technique and showed a major change in aluminium speciation after passage through a potable water treatment plant involving the addition of aluminium sulphate. There was a major increase in the Al(OH)x (3-x)+fraction, higher than Al(OH)3 solubility models predict, suggesting significant supersaturation of inorganic aluminium in the drinking water. © 1991, Taylor & Francis Group, LLC. All rights reserved.