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Oil-Water Transport in Clay-Hosted Nanopores: Effects of Long-Range Electrostatic Forces
  • Hao Xiong,
  • Deepak Devegowda,
  • Liangliang Huang
Hao Xiong
University of Oklahoma Norman Campus
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Deepak Devegowda
University of Oklahoma Norman Campus
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Liangliang Huang
University of Oklahoma
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Abstract

Charged clay surfaces can impact storage and mobility of hydrocarbon and water mixtures. Here, we use equilibrium molecular dynamics (MD) and nonequilibrium MD simulations to investigate hydrocarbon-water mixtures and their transport in slit-shaped illite nanopores. We construct two illite pore models with different surface chemistries: potassium-hydroxyl (P-H) and hydroxyl-hydroxyl (H-H) structures. In H-H nanopore, we observe water adsorption on the clay surfaces. In P-H nanopores, however, we observe the formation of water bridges or columns between the top and bottom pore surfaces. This is because of the existence of a local, long-range electric field within the P-H pore causing water molecules to align in a specific direction promoting the formation of a water bridge. Our NEMD simulations demonstrate that the velocity profiles across the pore depends strongly on the presence or absence of the water bridge. This study provides a theoretical basis for understanding of nanofluidics with charged surfaces.