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Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of Phosphorus(I)
Published on: November 22, 2016
Reductive dissolution of lead dioxide (PbO2) in acidic bromide solution.
Yi-Pin Lin1, Richard L Valentine
1Division of Environmental Science and Engineering, Faculty of Engineering, National University of Singapore, Singapore 117576. eselinyp@nus.edu.sg
Environmental Science & Technology
|April 28, 2010
Summary
Reductive dissolution of lead dioxide (PbO(2)(s)) in drinking water is clarified. Bromide and acid accelerate PbO(2)(s) dissolution through surface reactions and electron transfer, impacting lead levels.
Area of Science:
- Environmental Chemistry
- Surface Chemistry
- Geochemistry
Background:
- Reductive dissolution of lead dioxide (PbO(2)(s)) is a key pathway for elevated lead in drinking water.
- Surface processes governing this heterogeneous reaction remain poorly understood.
Purpose of the Study:
- To investigate the kinetics and mechanism of PbO(2)(s) reductive dissolution in acidic bromide solutions.
- To elucidate the detailed surface reactions involved in lead release.
Main Methods:
- Kinetic experiments were conducted in acidic bromide solutions.
- Reaction orders with respect to bromide and proton concentrations were determined.
- A surface reaction mechanism was proposed and validated against kinetic data.
Main Results:
- The reaction rate is proportional to PbO(2)(s) concentration.
- Reaction orders were determined as 1.08 for bromide and 1.77 for protons.
- A mechanism involving bromide adsorption, surface complex formation, and two one-electron transfers was elucidated.
Conclusions:
- Bromide adsorption and the first one-electron transfer are rate-limiting steps.
- The proposed surface reaction mechanism explains the observed kinetics.
- Similar mechanisms may apply to other reductive ions impacting metal oxides.
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