Effect of temperature on the dissolution of the lead (II) carbonate hydrocerussite for varying pH and dissolved inorganic carbon conditions

Abstract

The effect of temperature on the solubility of lead-bearing solid phases in water distribution systems for different water chemistry conditions remains unclear although lead concentrations are known to vary seasonally. The study objective is to explore the effect of temperature on the solubility of the lead(II) carbonate hydrocerussite under varying pH and DIC conditions. This is achieved through batch dissolution experiments conducted at multiple pHs (6–10) and DIC concentrations (20–200 mg CL⁻¹) at temperatures ranging from 5 to 40 °C. A thermodynamic model was also applied to evaluate the model’s ability to predict temperature effects on lead(II) carbonate solubility including solid phase transformations. In general, increasing temperature increased total dissolved lead at high pHs and the effect of temperature was greater for high DIC conditions, particularly for pH > 8. Temperature also influenced the pH at which the dominant lead(II) solid phase switched from hydrocerussite to cerussite (occurred between pH 7.25 to 10). Finally, the model was able to capture the overall trends observed despite thermodynamic data limitations. While this study focuses on a simple lead solid-aqueous system, findings provide important insights regarding the way in which temperature and water chemistry interact to affect lead concentrations.

Keywords:

• Hydrocerussite
• cerussite
• drinking water
• lead (II) carbonate
• temperature
• PHREEQC
• pH
• DIC
• modeling

Acknowledgments

The authors thank Caitlin Corcoran and RESTORE students for their assistance with the laboratory experiments. 

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author, C. Robinson upon reasonable request.

Additional information

Funding

This work was provided by a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant (03686-2015) to Robinson and Ontario Graduate Scholarship to Kushnir.