(257w) Microfluidic Study of CO2 Solubility in Aqueous Single and Mixed-Electrolyte Solutions

Comprehensive studies of phase equilibria of CO₂ in various aqueous electrolyte solutions are important to many applications such as CO₂ capture, storage and sequestration. Microfluidics (MF) can be a valuable tool for investigation of CO₂ mass transfer and solubility in electrolyte solutions, due to its superior mass and heat transfer, well-defined gas–liquid interfacial areas and the ability to vary reagent concentrations in a high-throughput manner. Uniformly sized bubbles of CO₂ were isothermally generated in co-flowing liquid streams with different compositions within a MF platform and the evolution of the bubble lengths were followed visually. The solubility of CO₂ in the solutions was obtained from a comparison between the terminal and the initial plug sizes. Measurements of CO₂ solubility in aqueous single electrolyte solutions (NaCl, Na₂SO₄, KCl, K₂SO₄, MgCl₂, MgSO₄ and CaCl₂) and aqueous mixed-electrolyte solutions at 298.15 K were performed in a microfluidic platform. The results of this work provide essential data for the development of comprehensive thermodynamic models for CO₂ solubility in geothermal brine solutions.