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AWWA WQTC71526
- Rates and Mechanisms of Lead (IV) Oxide Dissolution
- Conference Proceeding by American Water Works Association, 11/01/2009
- Publisher: AWWA
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In this study, the dissolution rates of pure plattnerite (ß-PbO<sub>2</sub>) were investigatedas a function of pH, dissolved inorganic carbon (DIC), orthophosphate, and the presenceof chloramines. A continuous stirred tank reactor (CSTR) loaded with 1 g/L ofplattnerite was used to measure the lead dissolution rates. The lead concentration and pHof the effluent were monitored continuously and reached steady-state values within oneday. The dissolution rates were on the order of 10<sup>-10</sup> mol/m<sup>2</sup>-min. At all pH valuesstudied (7.5, 8.5, and 10), the dissolution rate increased with increasing DIC, probablydue to the formation of soluble Pb-carbonate complexes. The fastest dissolution rateswere observed at the lowest pH of 7.5. The initial PbO<sub>2</sub> solid and possible transformationproducts were characterized by X-ray diffraction. Includes 16 references, figures.