In situ observation of the structure of crystallizing magnesium sulfate heptahydrate solutions with terahertz transmission spectroscopy
In situ observation of the structure of crystallizing magnesium sulfate heptahydrate solutions with terahertz transmission spectroscopy
Terahertz time-domain spectroscopy in a transmission geometry combined with visual analysis was used to investigate the crystallization process of MgSO4solution. Careful spectral analysis of both a feature at 1.6 THz and the overall magnitude of absorption allowed the extraction of information about the liquid phase before and during crystallization, aiding the investigation of solvation dynamics and the behavior of molecular species at phase boundaries. The method was reproducibly applied to a number of measurements on a series of solutions of three chosen concentrations at different temperatures. When increasing temperature at the end of the measurement, the dissolution of crystals was observed as well. The temperature-dependent absorption data of the semicrystalline systems were converted to the solvent concentrations using a recently developed method. Solutions of a series of concentrations were also investigated in the temperature range of 4-25 °C. The results were compared to the theoretical calculated values, and the consistent differences proved the existence of a hydration shell around the salt ions whose behavior is different from bulk water. Future work will focus on triggering nucleation at specific positions in order to study the very beginning of the crystallization process. MgSO4heptahydrate is used as a model system in this study, while the concept and the setup can be applied to other systems.
3961-3972
Li, Qi
193e5502-fc0d-4a67-8b41-ed4d8b560c2f
Kölbel, Johanna
54e6b7b7-8c1e-4fcf-955b-241e0a911b4b
Davis, Margaret P.
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Korter, Timothy M.
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Bond, Andrew D.
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Threlfall, Terrence
6c670746-9730-49fc-9381-e45ae4807450
Zeitler, J. Axel
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1 June 2022
Li, Qi
193e5502-fc0d-4a67-8b41-ed4d8b560c2f
Kölbel, Johanna
54e6b7b7-8c1e-4fcf-955b-241e0a911b4b
Davis, Margaret P.
91b8a7d8-f691-41ac-aaba-5bbadff2aee8
Korter, Timothy M.
49d1b031-e222-41eb-a432-5a587824429b
Bond, Andrew D.
94b1c5ea-ac6f-4062-9673-13064c82aeee
Threlfall, Terrence
6c670746-9730-49fc-9381-e45ae4807450
Zeitler, J. Axel
59b93a41-3e55-4aee-8f07-d150296fc12b
Li, Qi, Kölbel, Johanna, Davis, Margaret P., Korter, Timothy M., Bond, Andrew D., Threlfall, Terrence and Zeitler, J. Axel
(2022)
In situ observation of the structure of crystallizing magnesium sulfate heptahydrate solutions with terahertz transmission spectroscopy.
Crystal Growth and Design, 22 (6), .
(doi:10.1021/acs.cgd.2c00352).
Abstract
Terahertz time-domain spectroscopy in a transmission geometry combined with visual analysis was used to investigate the crystallization process of MgSO4solution. Careful spectral analysis of both a feature at 1.6 THz and the overall magnitude of absorption allowed the extraction of information about the liquid phase before and during crystallization, aiding the investigation of solvation dynamics and the behavior of molecular species at phase boundaries. The method was reproducibly applied to a number of measurements on a series of solutions of three chosen concentrations at different temperatures. When increasing temperature at the end of the measurement, the dissolution of crystals was observed as well. The temperature-dependent absorption data of the semicrystalline systems were converted to the solvent concentrations using a recently developed method. Solutions of a series of concentrations were also investigated in the temperature range of 4-25 °C. The results were compared to the theoretical calculated values, and the consistent differences proved the existence of a hydration shell around the salt ions whose behavior is different from bulk water. Future work will focus on triggering nucleation at specific positions in order to study the very beginning of the crystallization process. MgSO4heptahydrate is used as a model system in this study, while the concept and the setup can be applied to other systems.
Text
acs.cgd.2c00352
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More information
e-pub ahead of print date: 20 May 2022
Published date: 1 June 2022
Additional Information:
Funding Information:
J.K. thanks the EPSRC Cambridge Centre for Doctoral Training in Sensor Technologies and Applications (EP/L015889/1) and AstraZeneca for funding. Q.L. thanks the Chinese Scholarship Council for funding. M.P.D. and T.M.K. thank the ITS Research Computing team at Syracuse University for providing computational resources.
Identifiers
Local EPrints ID: 482366
URI: http://eprints.soton.ac.uk/id/eprint/482366
ISSN: 1528-7483
PURE UUID: 7843df91-d448-41f6-be17-f6f62faaf8a7
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Date deposited: 28 Sep 2023 16:37
Last modified: 17 Mar 2024 13:16
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Contributors
Author:
Qi Li
Author:
Johanna Kölbel
Author:
Margaret P. Davis
Author:
Timothy M. Korter
Author:
Andrew D. Bond
Author:
Terrence Threlfall
Author:
J. Axel Zeitler
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