Polyphosphate Water-Treatment Products: Their Effects on the Chemistry and Solubility of Lead in Potable Water Systems

摘要

Three commercial polyphosphate-containing water treatment products were evaluated for their ability to affect lead solubility in drinking water. A 'Competing-Ligand Spectrophotometry' Technique was used to characterize Pb(2+) complexation at 20 degrees C in ionic strength of 0.1, pH = 8, and calcium concentration of .001 mol/L. The pH was buffered by HEPES, and the colorimetric reagent was 4-(2-pyridylazo)-resourcinol (PAR). Results were also compared to a DPASV method. The data was fit by a 2- ligand model. The experiments suggested a significant ability to enhance lead solubility by complexation at the pH and hardness tested.