A study of the relationship between water and anions of the Hofmeister series using pressure perturbation calorimetry
Date
2015
Authors
Bye, J.W.
Falconer, R.J.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Physical Chemistry, Chemical Physics - PCCP, 2015; 17(21):14130-14137
Statement of Responsibility
Jordan W. Bye and Robert J. Falconer
Conference Name
Abstract
Pressure perturbation calorimetry (PPC) was used to study the relationship between water and sodium salts with a range of different anions. At temperatures around 25 °C the heat on pressurisation (ΔQ) from 1 to 5 bar was negative for all solutions relative to pure water. The raw data showed that as the temperature rose, the gradient was positive relative to pure water and the transition temperature where ΔQ was zero was related to anion surface charge density and was more pronounced for the low-charge density anions. A three component model was developed comprising bulk water, the hydration layer and the solute to calculate the molar expansivity of the hydration layer around the ions in solution. The calculated molar expansivities of water in the hydration layer around the ions were consistently less than pure water. ΔQ at different disodium hydrogen phosphate concentrations showed that the change in molar enthalpy relative to pure water was not linear even as it approached infinite dilution suggesting that while hydration layers can be allocated to the water around ions this does not rule out interactions between water and ions extending beyond the immediate hydration layer.
School/Discipline
Dissertation Note
Provenance
Description
Access Status
Rights
This journal is©the Owner Societies 2015. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.