Single-File Water Flux Through Two-Dimensional Nanoporous Membranes

Abstract

Recent advances in the development of two-dimensional (2D) materials have facilitated a wide variety of surface chemical characteristics obtained by composing atomic species, pore functionalization, etc. The present study focused on how chemical characteristics such as hydrophilicity affects the water transport rate in hexagonal 2D membranes. The membrane–water interaction strength was tuned to change the hydrophilicity, and the sub-nanometer pore was used to investigate single-file flux, which is known to retain excellent salt rejection. Due to the dewetting behavior of the hydrophobic pore, the water flux was zero or nominal below the threshold interaction strength. Above the threshold interaction strength, water flux decreased with an increase in interaction strength. From the potential of mean force analysis and diffusion coefficient calculations, the proximal region of the pore entrance was found to be the dominant factor degrading water flux at the highly hydrophilic pore. Furthermore, the superiority of 2D membranes over 3D membranes appeared to depend on the interaction strength. The present findings will have implications in the design of 2D membranes to retain a high water filtration rate.

The validity of the continuum modeling limit in a single pore flows to the molecular scale

“…This robust solid-liquid interaction results in an increased attraction of water molecules to the interfaces, thus giving rise to the higher-density peak. 55,[58][59][60] As we move from the interface towards a distance of approximately 1 nm, the attractive forces gradually diminish, leading to a reduction in density layering and converging towards the bulk value. It is a universal phenomenon for fluid molecules oscillating intensely close to solid surfaces.…”

Mathematical Simulation of Nanofiltration Process: State of Art Review

“…Suk 120 calculated the non-bounded interactions between the water molecules and membrane using the Lennard-Jones interaction (J/mol): V rr (28) where ε is the depth of the potential well (J/mol); σ is the distance between atoms at which the potential is equal to zero (Å); r is the distance between two atoms (Å).…”

A Molecular Dynamics Study Employing Bimetallic Co–CuHAB Nanosheets for Seawater Desalination

“…A class of materials examined extensively in recent years for developing RO membranes is metal–organic frameworks (MOFs), − which are fabricated from metal nodes such as zinc or iron being datively bonded to organic linkers. The design of MOFs entails a high degree of versatility, and their structures can be modified by replacing the organic linkers and/or the metal nodes.…”