Interfaces are present in every type of solutions, from a bubble formed in a liquid medium to complex multiphase systems found in biological and industrial processes. Their behavior can influence the transport phenomena, phase equilibria and adsorption, among others. Therefore, a reliable thermodynamic description of interfaces is important for understanding and predicting the behavior of many processes involving multicomponent fluids.
Although thermodynamic modelling of electrolyte solutions is a topic that gained attention the recent years, most established models focus primarily on homogeneous bulk phases. Considerably less known is the behavior of an electrolyte solution where the bulk meets another phase. In that region the density, composition and dielectric properties are expected to vary with position. Several theoretical approaches were developed for the description of inhomogeneous non-electrolyte solutions with particular focus given to Density Gradient Theory (DGT) and classical Density Functional Theory (cDFT). Those frameworks coupled with molecular equations of state can predict density profiles and interfacial properties.
The present project aims to study how an electrolyte equation of state model can be extended from bulk description to spatially inhomogeneous systems. The tools to be used for this implementation will include DGT and cDFT. Particular focus will be given to electrolyte specific contributions including electrostatic interactions, solvation and association effect and dielectric behavior in regard to their formulation inside the proposed framework. The developed approaches will be evaluated through predictions of density, ionic profiles, interfacial tension and related properties with the main objective of identifying which physical contributions can be transferred from bulk to interface and how their behavior is affected close to interfaces.
The PhD project is supported by European Research Counsil (ERC) grant as part of “REMOTE-Revolutionizing Molecular Thermodynamics by Water and Electrolytes” (Grand Agreement: 101171135, DOI: 10.3030/101171135).
Main supervisor:
Xiaodong Liang
Co- supervisor:
Georgios M. Kontogeorgis