Elucidating the mechanism of phenol exclusion and water permeation in graphyne anopore membranes: A combined DFT and reactive MD simulation study

G Chen and T Wu and ZY Zou and YF Wu, DIAMOND AND RELATED MATERIALS, 160, 113012 (2025).

DOI: 10.1016/j.diamond.2025.113012

In this study, reactive molecular dynamics (MD) simulations and density functional theory (DFT) calculations are used to investigate the selective water permeability and phenol removal effectiveness of graphyne-based membranes, with a particular focus on alpha- and gamma- graphyne nanopore structures. Our results show that one important factor influencing membrane selectivity is pore size. Because of its greater pore size, alpha-graphyne is able to block phenol molecules and transport water efficiently. On the other hand, gamma-graphyne's smaller pores limit its ability to transmit water. Analyses of charge density and population reveal a dynamic process of charge redistribution: water molecules gain a negative charge from bulk water polarization, which decreases as they come into contact with the graphyne rim. Water movement is facilitated by this process, but charge congestion prevents phenol penetration. Energy barrier investigation with DFT-revPBE further supports the improved permeability of alpha-graphyne, showing a nearly zero energy barrier in contrast to the high 1.96 eV barrier for gamma- graphyne. These findings highlight the unique electrical and structural characteristics controlling their filtration capabilities. The present study underscores the noteworthy possibilities of graphyne-based membranes for selective filtration, establishing alpha-graphyne as a prime contender for high-flux water purification and gamma-graphyne for uses requiring strict selectivity. For the logical design of cutting- edge materials for environmental governance and sustainable water treatment technologies, our understanding of the basic mechanics of selective permeation provides invaluable information.

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