论文标题
晶界和界面静电相互作用如何通过纳米多孔六角硼调节水的脱盐
How Grain Boundaries and Interfacial Electrostatic Interactions Modulate Water Desalination Via Nanoporous Hexagonal Boron Nitride
论文作者
论文摘要
研究人员目前正在探索纳米二维材料，例如六角硼（HBN），作为潜在的淡化膜。在这里，我们使用经典的分子动力学模拟，研究了由量子机械密度功能理论（DFT）计算支持的经典分子动力学模拟，研究了晶界（GB）和界面静电相互作用对双晶纳米孔HBN的脱盐性能的影响。我们研究了三种不同的纳米多孔双晶HBN构型，对称倾斜GB具有13.2°，21.8°和32.2°的不良定向角度。我们发现，与单晶HBN的纳米孔相比，晶界改变了双晶HBN中纳米孔的区域和形状。我们观察到，尽管具有13.2°不良角度的双晶纳米孔HBN显示水流速提高了〜30％，但与MonoCrystalline HBN相比，它表明Na $^\ MathRM {+} $ ion抑制减少了6％。我们还发现了纳米孔形状在水的脱脱系列中的作用，发现较小尺寸的细长毛孔（以21.8° - 和32.2° - 隔离的双晶HBN）可以通过较大尺寸的细长毛孔来匹配水的渗透，并具有较大的较大尺寸的毛孔，并具有相关的〜3-4％drop na $ $^$^$^\^\^\^\^\^\^\^\^\^\ flm^\ flm。模拟还预测，水流受到界面静电相互作用的显着影响。实际上，当使用DFT计算确定B原子上的部分电荷发生变化时，水流速最高，与未考虑部分电荷或批量部分电荷（即带电HBN）相比，水流量是最高的。总体而言，我们在双晶HBN中通过纳米孔进行水/离子传输的工作表明，GBS和表面电荷的存在可以分别导致HBN膜的离子排斥和水渗透性能下降。
Researchers are currently exploring nanoporous two-dimensional materials, such as hexagonal boron nitride (hBN), as potential desalination membranes. Here, we study the effect of grain boundaries (GBs) and interfacial electrostatic interactions on the desalination performance of bicrystalline nanoporous hBN, using classical molecular dynamics simulations supported by quantum-mechanical density functional theory (DFT) calculations. We investigate three different nanoporous bicrystalline hBN configurations, with symmetric tilt GBs having misorientation angles of 13.2°, 21.8°, and 32.2°. We find that grain boundaries alter the areas and shapes of nanopores in bicrystalline hBN, as compared to the nanopores in monocrystalline hBN. We observe that, although bicrystalline nanoporous hBN with a misorientation angle of 13.2° shows improved water flow rate by ~30%, it demonstrates reduced Na$^\mathrm{+}$ ion rejection by ~6%, as compared to monocrystalline hBN. We also uncover the role of the nanopore shape in water desalination, finding that more elongated pores with smaller sizes (in 21.8°- and 32.2°-misoriented bicrystalline hBN) can match the water permeation through less elongated pores of slightly larger sizes, with a concomitant ~3-4% drop in Na$^\mathrm{+}$ rejection. Simulations also predict that the water flow rate is significantly affected by interfacial electrostatic interactions. Indeed, the water flow rate is the highest when altered partial charges on B and N atoms were determined using DFT calculations, as compared to when no partial charges or bulk partial charges (i.e., charged hBN) were considered. Overall, our work on water/ion transport through nanopores in bicrystalline hBN indicates that the presence of GBs and surface charge can lead, respectively, to a drop in the ion rejection and water permeation performance of hBN membranes.
