Department
Chemistry
Major
Chemistry
Research Advisor
Switzer, Jay
Advisor's Department
Chemistry
Funding Source
Missouri S& T Opportunities for Undergraduate Research Experiences (OURE) Program NSF grants CHE-0437346 and DMR-0504715
Abstract
The strength of monochloramine, NH2CI, as an oxidizing agent can be linked to its effect on Pb levels in drinking water. In this study, the equilibrium potential was measured as a function of pH from pH 8-12 and compared to a theoretical plot of formal potentials derived from the Nernst equation. The measured equilibrium potential was consistently 300 mV more negative than the calculated potential. When the measured potentials are plotted on a Pourbaix diagram, it is found that NH2CI can oxidize Pb to PbO2 only above pH 9.5, while the theoretical values indicate that it can do so at a much lower pH. The validity of the values measured in this experiment is supported by the fact that NH2CI has been shown to oxidize Pb to Pb2•, not PbO2, at pH 8 (1). The work is important because it is known that PbO2 acts to passivate lead-bearing plumbing materials.
Biography
Brandi Clark is a junior in the Chemistry Department at the Missouri University of Science and Technology. She has been involved in research in both chemistry and civil/environmental engineering and has worked on several research projects, including two for OUR£ She is also actively involved in organizations in both departments including ASCE, WEF, the W T. Schrenk Society, and AX. [ Brandi plans to continue doing research and pursue a Ph.D. in chemistry, ideally with an emphasis on work in an environmental area.
Research Category
Natural Sciences
Presentation Type
Oral Presentation
Document Type
Presentation
Location
Havener Center, Carver Room
Presentation Date
9 April 2008, 9:00 am - 9:30 am
Unleaded Drinking Water: Equilibrium Potential Measurements for Monochloramine Disinfectant
Havener Center, Carver Room
The strength of monochloramine, NH2CI, as an oxidizing agent can be linked to its effect on Pb levels in drinking water. In this study, the equilibrium potential was measured as a function of pH from pH 8-12 and compared to a theoretical plot of formal potentials derived from the Nernst equation. The measured equilibrium potential was consistently 300 mV more negative than the calculated potential. When the measured potentials are plotted on a Pourbaix diagram, it is found that NH2CI can oxidize Pb to PbO2 only above pH 9.5, while the theoretical values indicate that it can do so at a much lower pH. The validity of the values measured in this experiment is supported by the fact that NH2CI has been shown to oxidize Pb to Pb2•, not PbO2, at pH 8 (1). The work is important because it is known that PbO2 acts to passivate lead-bearing plumbing materials.
