Atomistic understanding of functionalized γ-graphyne-1 nanosheet membranes for water desalination

Abstract

Water desalination is an important issue in the protection of environment and ecosystems; hence, the various nanostructured membranes were used as a substitute for the conventional membranes. In this regard, the performance of one-atom-thick γ-graphyne-1 nanosheets with different functional groups on their pore edges is investigated in this research for water desalination. In all of the previous works, only pristine graphyne-n (n ≥ 3) with inherent pores was used for water desalination, but their pore size was invariant. Therefore, we used γ-graphyne-1 to investigate the potential of the γ-graphyne-1 for water desalination using molecular dynamics simulation technique. The pristine γ-graphyne-1 was drilled and three types of functionalized pores were designed to study their capabilities in the water desalination process. The chemical functions of hydroxyl, fluorine and carboxylic acids were bonded to the pore edge of the γ-graphyne-1. The external hydrostatic pressure was applied to these reverse osmosis systems up to 50 MPa. The water permeability, salt rejection, potential of the mean force, water density profile, and water density map were calculated in this work. The results demonstrated that the functionalized γ-graphyne-1 can be effectively used for water desalination with high water flux and high salt rejection.