The Computing for Clean Water researchers have developed an equation which more accurately describes the flow rate of water passing through carbon nanotubes. They published a paper describing these initial findings.
"Friction of water slipping in carbon nanotubes"
Lay Person Abstract:
Carbon nanotubes are recently discovered molecular structures that resemble sub-microscopic soda straws made entirely out of carbon atoms. Among many of the unusual properties of carbon nanotubes, experiments have shown that water passes through these tubes much easier, in some cases 10,000 times easier, than what prior equations predicted. Using preliminary data computed using World Community Grid, the researchers have devised a new equation which predicts the flow rate of water through carbon nanotubes with much better accuracy. The predictions using the new equations also agree well with experimental results at varying flow rates. This represents an important step in the process of understanding the chemistry and physics involved in how water flows relatively freely through carbon nanotubes. The scientists hope this research will eventually lead to less costly and more efficient ways of purifying and removing salt from water.
Liquid slip is essential in nanofluidic systems as shrinking channel size leads to a dramatic increase of flow resistance and thus high energy consumption for driving non-slip flow. Using large scale non-equilibrium molecular dynamics simulation of water flowing in carbon nanotubes (CNTs), we show that the relationship between the CNT wall-water interfacial friction stress and slip velocity follows a transition-state-theory-based inverse hyperbolic sine function, which remains universally valid regardless of wetting properties, CNT chiralities and CNT sizes, and holds for all slip velocities from 0 to 1,400 m/s. The finding could benefit the research in desalination and other chemical purification techniques.
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