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Insights into the thermodynamics of surface reactions at the SiO2(s)/NaCl(aq) interface.

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Bibliographic Details
Title: Insights into the thermodynamics of surface reactions at the SiO2(s)/NaCl(aq) interface.
Authors: Korade, Karla1 (AUTHOR), Begović, Tajana1 (AUTHOR) tajana.chem@pmf.hr
Source: Journal of Thermal Analysis & Calorimetry. Feb2026, Vol. 151 Issue 4, p3031-3045. 15p.
Subjects: Surface reactions, Solid-liquid interfaces, Salt, Calorimetry, Silica nanoparticles, Proton transfer reactions, Thermodynamics
Abstract: This study investigates the behavior of silica nanoparticles suspended in an aqueous sodium chloride solution during wetting, as well as changes in pH and sodium chloride concentration. We examine the processes and interactions at the silica/aqueous electrolyte solution interface, which involve reactions among water molecules, dissolved ions and the electrically charged silica surface. The nanoparticles were characterized using dynamic light scattering and electrokinetic measurements to determine their size, electrokinetic potential, and stability in acidic conditions. We performed three types of calorimetric experiments with both a dissolution calorimeter and an isothermal titration calorimeter to analyze the thermodynamics of surface processes on the silica nanoparticles. Through theoretical analysis, we distinguished between the contributions of silica surface protonation and sodium ion association. Our findings reveal that the enthalpy change resulting from immersing dry silica nanoparticles in aqueous sodium chloride is exothermic. Importantly, the enthalpies associated with protonation are independent of pH and ionic strength, while those related to sodium ion association are affected by both pH and the charge of the silica nanoparticle surface. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
Description
Abstract:This study investigates the behavior of silica nanoparticles suspended in an aqueous sodium chloride solution during wetting, as well as changes in pH and sodium chloride concentration. We examine the processes and interactions at the silica/aqueous electrolyte solution interface, which involve reactions among water molecules, dissolved ions and the electrically charged silica surface. The nanoparticles were characterized using dynamic light scattering and electrokinetic measurements to determine their size, electrokinetic potential, and stability in acidic conditions. We performed three types of calorimetric experiments with both a dissolution calorimeter and an isothermal titration calorimeter to analyze the thermodynamics of surface processes on the silica nanoparticles. Through theoretical analysis, we distinguished between the contributions of silica surface protonation and sodium ion association. Our findings reveal that the enthalpy change resulting from immersing dry silica nanoparticles in aqueous sodium chloride is exothermic. Importantly, the enthalpies associated with protonation are independent of pH and ionic strength, while those related to sodium ion association are affected by both pH and the charge of the silica nanoparticle surface. [ABSTRACT FROM AUTHOR]
ISSN:13886150
DOI:10.1007/s10973-025-14710-x