A molecular dynamics study on the transport property prediction of brine in nanoconfined silica slits

P Qian and MY Gao and BH Wang and Y Shen and K Chen and J Zhang and DH Zhang, COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, 709, 136105 (2025).

DOI: 10.1016/j.colsurfa.2025.136105

The dynamic characteristics of brine in silica nanospaces with different wettability substrates, brine concentrations, and system scales were analyzed using molecular dynamics simulations. The test results of these systems were quantitatively compared based on key parameters such as density distributions, radial distribution functions, hydrogen bond dynamics, self-diffusion coefficients, and residence times. The results show that the cohesive force of water molecules affects the formation of adsorbed layer structures on silica with different wettability. Hydrophobic silica exhibits a uniform adsorption layer resembling a structured hydrogen bonding network, whereas hydrophilic silica surfaces exhibit a disordered hydration layer. Due to their electropositivity, sodium ions exhibit unique interaction dynamics with the silica surface, forming a hydration shell that impedes liquid flow. Furthermore, the diffusivity decreases with increasing salt concentration between hydrophilic and hydrophobic silica nanoplates, while larger system scale makes it less affected. In the saline environment involved in CO2 capture and storage, ions and system size have significant impacts on fluid transport and CO2 diffusion in geology. This discovery can enable relevant personnel to have a clearer understanding of these impacts and improve their understanding of the geological environment.

Return to Publications page