Geochemistry and speciation of Fe(II) and Fe(III) in natural geothermal water, Iceland
The geochemistry of Fe(II) and Fe(III) was studied in natural geothermal waters in Iceland. Samples of surface and spring water and sub-boiling geothermal well water were collected and analyzed for Fe(II), Fe(III) and Fetotal concentrations. The samples had discharge temperatures in the range 27–99...
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ftiupui:oai:scholarworks.iupui.edu:1805/14801 2023-10-09T21:52:42+02:00 Geochemistry and speciation of Fe(II) and Fe(III) in natural geothermal water, Iceland Kaasalainen, Hanna Stefánsson, Andri Druschel, Gregory K. Earth Science, School of Science 2017-12 application/pdf https://hdl.handle.net/1805/14801 en eng Elsevier 10.1016/j.apgeochem.2017.10.021 Applied Geochemistry Kaasalainen, H., Stefánsson, A., & Druschel, G. K. (2017). Geochemistry and speciation of Fe(II) and Fe(III) in natural geothermal water, Iceland. Applied Geochemistry, 87, 146-157. https://doi.org/10.1016/j.apgeochem.2017.10.021 https://hdl.handle.net/1805/14801 Publisher Policy Author iron redox speciation natural water Article 2017 ftiupui 2023-09-22T14:24:54Z The geochemistry of Fe(II) and Fe(III) was studied in natural geothermal waters in Iceland. Samples of surface and spring water and sub-boiling geothermal well water were collected and analyzed for Fe(II), Fe(III) and Fetotal concentrations. The samples had discharge temperatures in the range 27–99 °C, pH between 2.46 and 9.77 and total dissolved solids 155–1090 mg/L. The concentrations of Fe(II) and Fe(III) were determined in the <0.2 μm filtered and acidified fraction using a field-deployed ion chromatography spectrophotometry (IC-Vis) method within minutes to a few hours of sampling in order to prevent post-sampling changes. The concentrations of Fe(II) and Fe(III) were <0.1–130 μmoL/L and <0.2–42 μmoL/L, respectively. In-situ dialysis coupled with Fe(II) and Fe(III) determinations suggest that in some cases a significant fraction of Fe passing the standard <0.2 μm filtration method may be present in colloidal/particulate form. Therefore, such filter size may not truly represent the dissolved fraction of Fe but also nano-sized particles. The Fe(II) and Fe(III) speciation and Fetotal concentrations are largely influenced by the water pH, which in turn reflects the water type formed through various processes. In water having pH of ∼7–9, the total Fe concentrations were <2 μmoL/L with Fe(III) predominating. With decreasing pH, the total Fe concentrations increased with Fe(II) becoming increasingly important and predominating at pH < 3. In particular in waters having pH ∼6 and above, iron redox equilibrium may be approached with Fe(II) and Fe(III) possibly being controlled by equilibrium with respect to Fe minerals. In many acid waters, the Fe(II) and Fe(III) distribution may not have reached equilibrium and be controlled by the source(s), reaction kinetics or microbial reactions. Article in Journal/Newspaper Iceland Indiana University - Purdue University Indianapolis: IUPUI Scholar Works |
institution |
Open Polar |
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Indiana University - Purdue University Indianapolis: IUPUI Scholar Works |
op_collection_id |
ftiupui |
language |
English |
topic |
iron redox speciation natural water |
spellingShingle |
iron redox speciation natural water Kaasalainen, Hanna Stefánsson, Andri Druschel, Gregory K. Geochemistry and speciation of Fe(II) and Fe(III) in natural geothermal water, Iceland |
topic_facet |
iron redox speciation natural water |
description |
The geochemistry of Fe(II) and Fe(III) was studied in natural geothermal waters in Iceland. Samples of surface and spring water and sub-boiling geothermal well water were collected and analyzed for Fe(II), Fe(III) and Fetotal concentrations. The samples had discharge temperatures in the range 27–99 °C, pH between 2.46 and 9.77 and total dissolved solids 155–1090 mg/L. The concentrations of Fe(II) and Fe(III) were determined in the <0.2 μm filtered and acidified fraction using a field-deployed ion chromatography spectrophotometry (IC-Vis) method within minutes to a few hours of sampling in order to prevent post-sampling changes. The concentrations of Fe(II) and Fe(III) were <0.1–130 μmoL/L and <0.2–42 μmoL/L, respectively. In-situ dialysis coupled with Fe(II) and Fe(III) determinations suggest that in some cases a significant fraction of Fe passing the standard <0.2 μm filtration method may be present in colloidal/particulate form. Therefore, such filter size may not truly represent the dissolved fraction of Fe but also nano-sized particles. The Fe(II) and Fe(III) speciation and Fetotal concentrations are largely influenced by the water pH, which in turn reflects the water type formed through various processes. In water having pH of ∼7–9, the total Fe concentrations were <2 μmoL/L with Fe(III) predominating. With decreasing pH, the total Fe concentrations increased with Fe(II) becoming increasingly important and predominating at pH < 3. In particular in waters having pH ∼6 and above, iron redox equilibrium may be approached with Fe(II) and Fe(III) possibly being controlled by equilibrium with respect to Fe minerals. In many acid waters, the Fe(II) and Fe(III) distribution may not have reached equilibrium and be controlled by the source(s), reaction kinetics or microbial reactions. |
author2 |
Earth Science, School of Science |
format |
Article in Journal/Newspaper |
author |
Kaasalainen, Hanna Stefánsson, Andri Druschel, Gregory K. |
author_facet |
Kaasalainen, Hanna Stefánsson, Andri Druschel, Gregory K. |
author_sort |
Kaasalainen, Hanna |
title |
Geochemistry and speciation of Fe(II) and Fe(III) in natural geothermal water, Iceland |
title_short |
Geochemistry and speciation of Fe(II) and Fe(III) in natural geothermal water, Iceland |
title_full |
Geochemistry and speciation of Fe(II) and Fe(III) in natural geothermal water, Iceland |
title_fullStr |
Geochemistry and speciation of Fe(II) and Fe(III) in natural geothermal water, Iceland |
title_full_unstemmed |
Geochemistry and speciation of Fe(II) and Fe(III) in natural geothermal water, Iceland |
title_sort |
geochemistry and speciation of fe(ii) and fe(iii) in natural geothermal water, iceland |
publisher |
Elsevier |
publishDate |
2017 |
url |
https://hdl.handle.net/1805/14801 |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
Author |
op_relation |
10.1016/j.apgeochem.2017.10.021 Applied Geochemistry Kaasalainen, H., Stefánsson, A., & Druschel, G. K. (2017). Geochemistry and speciation of Fe(II) and Fe(III) in natural geothermal water, Iceland. Applied Geochemistry, 87, 146-157. https://doi.org/10.1016/j.apgeochem.2017.10.021 https://hdl.handle.net/1805/14801 |
op_rights |
Publisher Policy |
_version_ |
1779315878336135168 |