Journal article
Schwertmannite transformation under strongly-acidic conditions favoring jarosite precipitation: The effect of arsenic(V) and temperature
Journal of hazardous materials, Vol.514, pp.1-16
08/2026
PMID: 42372412
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Abstract
Schwertmannite is an Fe(III) oxyhydroxysulfate that can host large amounts of As(V) in acid mine drainage (AMD) systems. However, schwertmannite is metastable and transforms over time to jarosite and/or goethite under strongly-acidic (pH < 3) AMD conditions. This study provides the first quantitative evaluation of schwertmannite transformation kinetics under these conditions, examining the combined effects of As(V) loading (As:Fe ratios spanning 0-0.0667) and temperature (20, 40 and 60 °C). Compositional analyses, X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) spectroscopy, coupled with fitting of reaction progress data using the Avrami kinetic model, reveals that schwertmannite transformation responds systematically to As(V) loading in multiple ways that vary as a function of temperature. At 20°C and 40°C, schwertmannite transformed readily to jarosite at all As(V) loadings, with half transformation times (t<sub>50</sub>) spanning 47-164 days at 20°C and 12-33 days at 40°C. In contrast, schwertmannite transformation to goethite was inhibited by As(V) at 20°C and 40°C (with no goethite detected in any As(V)-bearing treatment). At 60°C, As(V) also retarded schwertmannite transformation to goethite, although goethite formation was not completely inhibited at this higher temperature until As:Fe ratios exceeded 0.025. Conversely, transformation of schwertmannite to jarosite at 60°C was accelerated by increases in As(V), with t<sub>50</sub> dropping from ∼7 days under As(V)-free conditions to ∼4 days at the highest As(V) loading. Apparent activation energies for schwertmannite transformation to jarosite increased with As(V), indicating that this mineralogical transformation becomes more energy demanding at higher As(V) loadings.
Details
- Title
- Schwertmannite transformation under strongly-acidic conditions favoring jarosite precipitation: The effect of arsenic(V) and temperature
- Creators
- Neal Bailey - Southern Cross UniversityNiloofar Karimian - Monash UniversityScott G Johnston - Southern Cross UniversityMona Hosseinpour Moghaddam - Southern Cross UniversityDane Lamb - RMIT UniversityEdward D Burton - Southern Cross University
- Publication Details
- Journal of hazardous materials, Vol.514, pp.1-16
- Publisher
- Elsevier B.V.
- Grant note
- This research was supported by the Australian Research Council (Project FT200100449) and by additional financial assistance from Southern Cross University.
- Identifiers
- 991013386550302368
- Copyright
- © 2026 The Author(s).
- Academic Unit
- Faculty of Science and Engineering; Science
- Language
- English
- Resource Type
- Journal article