The pH-dependence of scorodite dissolution kinetics

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Authors:Griffith, Martha; Harvey, Mary; Schreiber, Madeline
Author Affiliations:Primary:
Virginia Polytechnic Institute and State University, Department of Geosciences, Blacksburg, VA, United States
Volume Title:Geological Society of America, 2005 annual meeting
Source:Abstracts with Programs - Geological Society of America, 37(7), p.377; Geological Society of America, 2005 annual meeting, Salt Lake City, UT, Oct. 16-19, 2005. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592
Publication Date:2005
Note:In English
Summary:Scorodite (FeAsO4 · 2H2O) occurs naturally as an arsenic-bearing alteration product of arsenopyrite (FeAsS). It is important to understand what controls the release of arsenic into natural systems, as arsenic is a human carcinogen and toxin. The purpose of this research is to evaluate the dissolution kinetics of scorodite as a function of pH. Previous studies of scorodite dissolution have shown that scorodite is stable around a pH of 2 (Dove and Rimstidt 1985; Demopoulos 2005). The dissolution kinetics of scorodite as a function of temperature was studied by Harvey (2004) and was found to increase with temperature. In the current study, the rate of scorodite dissolution is being examined at pH values between 2 and 7, as this pH range is typical in sulfide mine settings. Preliminary results for pH 3 and 5 show that the rate of scorodite dissolution is approximately 10-10.51 mol/m2sec at pH 3, and increases to 10-10.11 mol/m2sec at pH 5, indicating that the rate of scorodite dissolution increases with pH.
Subjects:Alteration; Arsenates; Arsenic; Controls; Kinetics; Medical geology; Metals; PH; Pollution; Scorodite; Solution; Temperature; Toxic materials
Record ID:2006080650
Copyright Information:GeoRef, Copyright 2018 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
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