A Molecular Dynamics Study on Rotational Nanofluid and Its Application to Desalination

Abstract

In this work, we systematically study a rotational nanofluidic device for reverse osmosis (RO) desalination by using large scale molecular dynamics modeling and simulation. Moreover, we have compared Molecular Dynamics simulation with fluid mechanics modeling. We have found that the pressure generated by the centrifugal motion of nanofluids can counterbalance the osmosis pressure developed from the concentration gradient, and hence provide a driving force to filtrate fresh water from salt water. Molecular Dynamics modeling of two different types of designs are performed and compared. Results indicate that this novel nanofluidic device is not only able to alleviate the fouling problem significantly, but it is also capable of maintaining high membrane permeability and energy efficiency. The angular velocity of the nanofluids within the device is investigated, and the critical angular velocity needed for the fluids to overcome the osmotic pressure is derived. Meanwhile, a maximal angular velocity value is also identified to avoid Taylor-Couette instability. The MD simulation results agree well with continuum modeling results obtained from fluid hydrodynamics theory, which provides a theoretical foundation for scaling up the proposed rotational osmosis device. Successful fabrication of such rotational RO membrane centrifuge may potentially revolutionize the membrane desalination technology by providing a fundamental solution to the water resource problem.

A Comprehensive Analysis of the Impact of Inorganic Matter on Membrane Organic Fouling: A Mini Review

“…The interactions between atoms or molecules are described by a force field potential, which includes terms representing bond stretching, angle bending, and non-bonded interactions such as electrostatic forces and van der Waals forces. It provides valuable insights into the behavior and properties of molecular systems that are difficult or impossible to study experimentally, offering a powerful tool for scientific research and discovery [58][59][60][61].…”

Differences in the Effect of Mn2+ on the Reverse Osmosis Membrane Fouling Caused by Different Types of Organic Matter: Experimental and Density Functional Theory Evidence

“…Density functional theory (DFT) calculations have been widely used for modeling and predicting reactions between substances and have been used in membrane fouling studies [8,11,21,22]. Because of the lack of a research base related to RO membrane fouling exacerbated by Mn 2+ , DFT would be a good aid in interpreting the results.…”