Dhondi Pradeep

Water and Ion Transport Through Functionalized Nanopores 2D Materials

Two-dimensional (2D) materials, consisting of a few atomic layers, are extensively researched for various applications, including seawater desalination. These materials can be engineered to contain nanopores, whose size, shape, and chemical character significantly affect the material’s performance as a membrane. Accordingly, nanoporous 2D materials and their functionalized forms have emerged as promising membrane materials for water desalination applications due to their remarkable mechanical strength, high water permeance, and excellent selectivity. In this regard, recent studies have demonstrated that the chemical functionalization of nanopores in graphene (for example, by adding hydroxyl groups) can enhance water permeability and provide 100% rejection of salt ions [1]. In this work, we examine both functionalized and unfunctionalized nanoporous hexagonal boron nitride (hBN) membranes for desalination with different salt solutions via molecular dynamics (MD) simulations. Our MD simulations reveal a significantly higher water permeance through hBN membranes, as compared to the typical water permeance of current polymeric membranes, which is around 0.1 L.cm-2.day-1.MPa-1. We find that functionalized nanopores in hBN (with hydrogen atoms at the edges) demonstrate a slightly lower water flux and higher overall ion rejection, as compared to unfunctionalized nanopores. Moreover, by studying ions of various charges and sizes, our study unravels the complex interplay between ion characteristics and membrane functionalization and their effects on the desalination performance of nanoporous hBN membranes. These findings have significant implications for the advancement of membrane technology, as they offer valuable insights that can be leveraged to design improved membranes for more efficient water desalination processes.