(93i) Towards Connecting the Microstructural and Structural Changes in Hierarchical Nanoporous Materials (e.g., clays) during Gas Adsorption (CO2, CH4, H2) Using in-Operando Multi-Scale X-Ray and Neutron Scattering Measurements

A fundamental understanding of the effect of gas adsorption and desorption behaviors at solid-water interfaces on the structures and microstructures of nano-porous materials has implications for engineered gas separations, and for engineering gas transport, recovery, and storage processes in subsurface environments. In this study, the effects of gas (e.g., CO₂, CH₄, H₂) adsorption and desorption behaviors on the structural and microstructural changes in nanoporous materials (e.g., clays such as Na-montmorillonite) with variable amounts of nano-confined interlayer water are investigated. The dynamic effects of gas adsorption and desorption on the molecular structure, the nano-confined interlayer water, the interlayer nanoporosity, and the meso-scale porosity are probed using multi-scale X-ray scattering methods which encompass Ultra-Small Angle, Small-Angle, and Wide-Angle X-ray Scattering (USAXS/SAXS/WAXS). Further, the application of contrast variation methods applied in Ultra-Small Angle and Small-Angle Neutron Scattering (USANS/SANS) methods allow us to investigate the displacement of nano-confined fluids during gas adsorption and desorption while quantifying the bulk gas uptake and release rates.