Interfacial Properties of the Hexane+Carbon Dioxide+Water System in the Presence of Hydrophilic Silica

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7 Scopus citations

Abstract

Molecular dynamics simulations were conducted to study the interfacial behavior of the CO2+H2O and hexane+CO2+H2O systems in the presence of hydrophilic silica at geological conditions. Simulation results for the CO2+H2O and hexane+CO2+H2O systems are in reasonable agreement with the theoretical predictions based on the density functional theory. In general, the interfacial tension (IFT) of the CO2+H2O system exponentially (linearly) decreased with increasing pressure (temperature). The IFTs of the hexane+CO2+H2O (two-phase) system decreased with increasing mole fraction of CO2 in the hexane/CO2-rich phase xCO2. Here the negative surface excesses of hexane lead to a general increase in the IFTs with increasing pressure. The effect of pressure on these IFTs decreased with increasing xCO2 due to the positive surface excesses of carbon dioxide. The simulated water contact angles of the CO2+H2O+silica system fall in the range from 43.8 to 76.0o, which is in reasonable agreement with the experimental results. These contact angles increased with pressure and decreased with temperature. Here the adhesion tensions are influenced by variations in fluid-fluid IFT and contact angle. The simulated water contact angles of the hexane+H2O+silica system fall in the range from 58.0 to 77.0o and are not much affected by the addition of CO2. These contact angles increased with pressure and the pressure effect was less pronounced at lower temperatures. Here the adhesion tensions are mostly influenced by variations in fluid-fluid IFTs. In all studied cases, CO2 molecules could penetrate into the interfacial region between the water droplet and the silica surface.
Original languageEnglish (US)
JournalThe Journal of chemical physics
DOIs
StatePublished - Nov 22 2022

Bibliographical note

KAUST Repository Item: Exported on 2022-11-29
Acknowledged KAUST grant number(s): OSR-2019-CRG8-4074
Acknowledgements: This work is supported by the King Abdullah University of Science and Technology, Office of Sponsored Research, under Award No. OSR-2019-CRG8-4074. This work is also partly supported by the National Natural Science Foundation of China (Grant No. 42203041) and the Natural Science Foundation of Jiangsu Province (Grant No. BK20221132), China.

ASJC Scopus subject areas

  • General Physics and Astronomy
  • Physical and Theoretical Chemistry

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