TY - GEN
T1 - Lead(IV) oxide formation from lead(0) and lead(II) precursors at conditions relevant to drinking water distribution
AU - Wang, Yin
AU - Xie, Yanjiao
AU - Li, Wenlu
AU - Wang, Zimeng
AU - Giammar, Daniel E.
PY - 2010
Y1 - 2010
N2 - Lead(IV) oxide is a corrosion product that develops on lead pipes used for drinking water supply, and its stability can control lead concentrations in tap water. The rate and extent of lead(IV) oxide formation is affected by water chemistry. Water chemistry can also control which specific lead(IV) oxide, scrutinyite (α-PbO2) or plattnerite (β-PbO2), is formed. Knowledge of the mechanisms of lead(IV) oxide formation and the identity of the lead(IV) oxide phases present can be useful for predicting lead release in response to changes of the water chemistry. Such knowledge can be valuable for managing lead concentrations in drinking water distribution systems. A set of batch experiments were performed to examine the formation of lead(IV) oxide as a function of time, pH, the presence of dissolved inorganic carbon (DIC), and free chlorine concentration. Experiments were conducted with lead(0) powder and four lead(II) compounds that are precursors for lead(IV) oxide formation: lead(II) chloride (PbCl2), massicot (β-PbO), cerussite (PbCO3), and hydrocerussite (Pb3(OH) 2(CO3)2). Experiments were conducted for up to 1 month, and the pH and free chlorine concentration were monitored regularly. The solids were characterized following different reaction times by X-ray diffraction and scanning electron microscopy to identify secondary phases and observe changes in particle morphology. Lead(IV) oxide formed in the absence as well as the presence of DIC. The identity of the lead(IV) oxide was strongly related to the starting phases. Scrutinyite formed from hydrocerussite, and mixtures of scrutinyite and plattnerite formed from massicot and cerussite. At pH 7.5, a mixture of scrutinyite and plattnerite formed from lead(II) chloride solution, while at pH 10, pure plattnerite formed due to the formation of an intermediate lead(II) oxide chloride (Pb4O3Cl 2.H2O) solid. When starting with massicot, the presence of DIC increased the formation rate of lead(IV) oxide and changed the identity of lead(IV) oxide formed. The identity of lead(IV) oxide formed was pH-dependent in the presence of DIC. Lower pH favored plattnerite£¬ and higher pH resulted in scrutinyite formation. However, this trend was not observed in the absence of DIC. These results indicate that DIC affected the mechanism of lead(IV) oxide formation by promoting the precipitation of different intermediate solids. 2010
AB - Lead(IV) oxide is a corrosion product that develops on lead pipes used for drinking water supply, and its stability can control lead concentrations in tap water. The rate and extent of lead(IV) oxide formation is affected by water chemistry. Water chemistry can also control which specific lead(IV) oxide, scrutinyite (α-PbO2) or plattnerite (β-PbO2), is formed. Knowledge of the mechanisms of lead(IV) oxide formation and the identity of the lead(IV) oxide phases present can be useful for predicting lead release in response to changes of the water chemistry. Such knowledge can be valuable for managing lead concentrations in drinking water distribution systems. A set of batch experiments were performed to examine the formation of lead(IV) oxide as a function of time, pH, the presence of dissolved inorganic carbon (DIC), and free chlorine concentration. Experiments were conducted with lead(0) powder and four lead(II) compounds that are precursors for lead(IV) oxide formation: lead(II) chloride (PbCl2), massicot (β-PbO), cerussite (PbCO3), and hydrocerussite (Pb3(OH) 2(CO3)2). Experiments were conducted for up to 1 month, and the pH and free chlorine concentration were monitored regularly. The solids were characterized following different reaction times by X-ray diffraction and scanning electron microscopy to identify secondary phases and observe changes in particle morphology. Lead(IV) oxide formed in the absence as well as the presence of DIC. The identity of the lead(IV) oxide was strongly related to the starting phases. Scrutinyite formed from hydrocerussite, and mixtures of scrutinyite and plattnerite formed from massicot and cerussite. At pH 7.5, a mixture of scrutinyite and plattnerite formed from lead(II) chloride solution, while at pH 10, pure plattnerite formed due to the formation of an intermediate lead(II) oxide chloride (Pb4O3Cl 2.H2O) solid. When starting with massicot, the presence of DIC increased the formation rate of lead(IV) oxide and changed the identity of lead(IV) oxide formed. The identity of lead(IV) oxide formed was pH-dependent in the presence of DIC. Lower pH favored plattnerite£¬ and higher pH resulted in scrutinyite formation. However, this trend was not observed in the absence of DIC. These results indicate that DIC affected the mechanism of lead(IV) oxide formation by promoting the precipitation of different intermediate solids. 2010
UR - https://www.scopus.com/pages/publications/84873513745
M3 - Conference contribution
AN - SCOPUS:84873513745
SN - 9781617823404
T3 - Water Quality Technology Conference and Exposition 2010
SP - 3025
EP - 3034
BT - Water Quality Technology Conference and Exposition 2010
T2 - Water Quality Technology Conference and Exposition 2010
Y2 - 14 November 2010 through 18 November 2010
ER -