Work

Hydrogen solubility in aqueous solutions: A thermodynamic modeling approach using electrolyte equation of state

Year: 2026

Type: article

Abstract: Accurate prediction of hydrogen solubility in aqueous solutions is essential for evaluating the feasibility and safety of underground hydrogen storage. This study applies an electrolyte version of the Cubic-Plus-Association (eCPA) Equation of State to model hydrogen solubility in both pure water and aqueous sodium chloride solutions. For hydrogen solubility in pure water (up to 497.5 K and 102.7 MPa), the model achieves a relative average deviation of 3.6%. In sodium chloride solutions (up to 373.9 K, 20.1 MPa, and 5.3 mol/kg), the deviation is further reduced to 2.7%. The model effectively captures key thermodynamic behaviors, including the salting-out effect, where ion hydration reduces gas solubility, and the temperature inversion phenomenon observed in pure water. This work establishes a robust thermodynamic framework for hydrogen storage applications and provides a foundational tool for analyzing phase equilibria in aqueous hydrogen systems. • Extending the applicability of e-CPA model to hydrogen systems. • The model shows good agreement with experimental data across wide temperature, pressure, and salinity ranges. • Temperature inversion of hydrogen solubility is explained via molecular-level thermodynamic effects. • Salting-out effects are linked to ion hydration and reduced hydrogen–water interactions.

Source: International Journal of Hydrogen Energy

DOI: 10.1016/j.ijhydene.2026.153964

Authors: Li Sun, Tingting Zhu, Jierong Liang

Institutions: Hohai University, Shanghai Ocean University, University of Twente, Helmholtz-Zentrum Dresden-Rossendorf, Dresden High Magnetic Field Laboratory

Language: English

Topic: Phase Equilibria and Thermodynamics

Subfield: Biomedical Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: hybrid

Estimated APC paid: $3,730