In-situ Raman spectroscopic analysis of phase transition temperatures in silica interacting with water and NaCl solutions

Abstract Phase transition temperatures of pure water and aqueous sodium chloride (NaCl) solutions, both in bulk form and mixed with the silica (SiO2) powder, were investigated using in-situ Raman spectroscopy. To determine the freezing and melting temperatures, the OH-stretching and bending regions...

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Main Authors: Krishnakumari Pamula, Amol Pophali, Dilip Gersappe, Taejin Kim
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-12034-2
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author Krishnakumari Pamula
Amol Pophali
Dilip Gersappe
Taejin Kim
author_facet Krishnakumari Pamula
Amol Pophali
Dilip Gersappe
Taejin Kim
author_sort Krishnakumari Pamula
collection DOAJ
description Abstract Phase transition temperatures of pure water and aqueous sodium chloride (NaCl) solutions, both in bulk form and mixed with the silica (SiO2) powder, were investigated using in-situ Raman spectroscopy. To determine the freezing and melting temperatures, the OH-stretching and bending regions of the Raman spectrum were analysed, along with investigation of hydrohalite (HH) formation in saline water. A spectral phase transition marker, SD, defined as the intensity ratio of asymmetric to symmetric OH-stretching bands (Iasym/Isym), was applied to measure the freezing and melting temperatures. In the case of bulk water and aqueous salt solutions, complete tranformation of liquid to solid phase was noticed. However, in the case of SiO2 mixed liquids, a non-freezable liquid layer was observed, which could be due to the interaction between the silanol (Si–OH) functional groups and the water/NaCl solution. These findings are expected to provide valuable insights into the freezing and thawing processes in both normal and saline soil in cold regions.
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spelling doaj-art-a3bfaf8ea4594d59bdd4bca0137259d72025-08-20T04:02:45ZengNature PortfolioScientific Reports2045-23222025-07-0115111510.1038/s41598-025-12034-2In-situ Raman spectroscopic analysis of phase transition temperatures in silica interacting with water and NaCl solutionsKrishnakumari Pamula0Amol Pophali1Dilip Gersappe2Taejin Kim3Department of Materials Science and Chemical Engineering, Stony Brook UniversityDepartment of Materials Science and Chemical Engineering, Stony Brook UniversityDepartment of Materials Science and Chemical Engineering, Stony Brook UniversityDepartment of Materials Science and Chemical Engineering, Stony Brook UniversityAbstract Phase transition temperatures of pure water and aqueous sodium chloride (NaCl) solutions, both in bulk form and mixed with the silica (SiO2) powder, were investigated using in-situ Raman spectroscopy. To determine the freezing and melting temperatures, the OH-stretching and bending regions of the Raman spectrum were analysed, along with investigation of hydrohalite (HH) formation in saline water. A spectral phase transition marker, SD, defined as the intensity ratio of asymmetric to symmetric OH-stretching bands (Iasym/Isym), was applied to measure the freezing and melting temperatures. In the case of bulk water and aqueous salt solutions, complete tranformation of liquid to solid phase was noticed. However, in the case of SiO2 mixed liquids, a non-freezable liquid layer was observed, which could be due to the interaction between the silanol (Si–OH) functional groups and the water/NaCl solution. These findings are expected to provide valuable insights into the freezing and thawing processes in both normal and saline soil in cold regions.https://doi.org/10.1038/s41598-025-12034-2WaterSaline waterSiO2 powderRaman spectroscopyFreezing temperatureMelting temperature
spellingShingle Krishnakumari Pamula
Amol Pophali
Dilip Gersappe
Taejin Kim
In-situ Raman spectroscopic analysis of phase transition temperatures in silica interacting with water and NaCl solutions
Scientific Reports
Water
Saline water
SiO2 powder
Raman spectroscopy
Freezing temperature
Melting temperature
title In-situ Raman spectroscopic analysis of phase transition temperatures in silica interacting with water and NaCl solutions
title_full In-situ Raman spectroscopic analysis of phase transition temperatures in silica interacting with water and NaCl solutions
title_fullStr In-situ Raman spectroscopic analysis of phase transition temperatures in silica interacting with water and NaCl solutions
title_full_unstemmed In-situ Raman spectroscopic analysis of phase transition temperatures in silica interacting with water and NaCl solutions
title_short In-situ Raman spectroscopic analysis of phase transition temperatures in silica interacting with water and NaCl solutions
title_sort in situ raman spectroscopic analysis of phase transition temperatures in silica interacting with water and nacl solutions
topic Water
Saline water
SiO2 powder
Raman spectroscopy
Freezing temperature
Melting temperature
url https://doi.org/10.1038/s41598-025-12034-2
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