Computer-Aided Design of Boron Nitride-Based Membranes with Armchair and Zigzag Nanopores for Efficient Water Desalination

Abstract

Recent studies have shown that the use of membranes based on artificial nanoporous materials can be effective for desalination and decontamination of water, separation of ions and gases as well as for solutions to other related problems. Before the expensive stages of synthesis and experimental testing, the search of the optimal dimensions and geometry of nanopores for the water desalination membranes can be done using computer-aided design. In the present study, we propose and examine the assumption that rectangular nanopores with a high aspect ratio would demonstrate excellent properties in terms of water permeation rate and ion rejection. Using the non-equilibrium molecular dynamic simulations, the properties of promising hexagonal boron nitride (h-BN) membranes with rectangular nanopores were predicted. It has been found that not only the nanopore width but also its design (“armchair” or “zigzag”) determines the permeability and ion selectivity of the h-BN-based membrane. The results show that membranes with a zigzag-like design of nanopores of ~6.5 Å width and the armchair-like nanopores of ~7.5 Å width possess better efficiency compared with other considered geometries. Moreover, the estimated efficiency of these membranes is higher than that of any commercial membranes and many other previously studied single-layer model membranes with other designs of the nanopores.

How Grain Boundaries and Interfacial Electrostatic Interactions Modulate Water Desalination via Nanoporous Hexagonal Boron Nitride

“…Besides the above-mentioned 2D nanosheets, hBN nanosheets have also been investigated as separation membranes by various researchers. ,,,,,,− Chen et al experimentally examined the water transport performance of amino-functionalized nanoporous hBN using a positive pressure setup. They found that the hBN membranes are highly stable in various organic solvents and water and showed high water flux and excellent selectivity in organic and aqueous solvents.…”

“…In fact, it was even higher than that through nanoporous graphene. Other studies focusing on unraveling the role of doping, nanopore edge functionalization, ,, and edge type in modulating water permeation have also been carried out. Nevertheless, in the above-mentioned studies, the electrical potential produced by nanoporous hBN was not validated with quantum–mechanical DFT calculations, although the charges on B and N atoms were derived using some DFT-based charge partitioning schemes.…”