Hamed Mashhadzadeh Amin, Zarghami Dehaghani Maryam, Vafa Narges, Firoozabadi Bahar, Golman Boris, Spitas Christos, Kostas Konstantinos V
Department of Chemical and Materials Engineering, School of Engineering and Digital Sciences, Nazarbayev University, 53 Kabanbay Batyr Ave., Astana, 010000, Kazakhstan.
Department of Chemical and Materials Engineering, School of Engineering and Digital Sciences, Nazarbayev University, 53 Kabanbay Batyr Ave., Astana, 010000, Kazakhstan.
J Mol Graph Model. 2025 Jan;134:108905. doi: 10.1016/j.jmgm.2024.108905. Epub 2024 Nov 9.
The global shortage of freshwater resources has spurred significant interest among scientists in the development of cost-effective and highly efficient water desalination methods. The forward osmosis (FO) membrane has become well-known for its various advantages, such as its low energy usage, cost-effective performance, high efficiency in desalination, and minimal fouling. Herein, the desalination performance of an FO system containing a boron-nitride slit membrane (BNSM) was investigated using molecular dynamics (MD) simulations. The effects of parameters, including slit width, temperature, draw solution (DS) concentration, and its types (MgCl, CaCl, and KCl), on salt ion rejections and water flow rate were explored. The rejection percentages of Na and Mg ions decreased from 100 % to 94 % and 96 %, respectively, as the slit width increased from 6 Å to 9 Å. Additionally, the water flow rate increased significantly, from 17.305 to 80.92 molecules/ns, with the same increase in slit width. The temperature elevation led to a decrease in ion rejection percentage and increased the water flow rate, since, according to the Stokes-Einstein equation, the diffusion coefficient of spherical particles increases with increasing temperature. The changes in DS concentration did not affect the ion rejection performance due to the small size of the slit width as well as the dominant effect of size exclusion. The increase in the DS concentration caused concentration polarization and a decrease in osmotic pressure resulting in a drop in the water flow rate. Due to the highest hydration radius of K ions, the rejection percentages of Mg and Ca ions were higher, while the Na ion rejection percentages had the highest and lowest values in systems having DS of CaCl and KCl, respectively, which was in accordance with the trend of water flow rate.
全球淡水资源短缺促使科学家们对开发具有成本效益和高效的海水淡化方法产生了浓厚兴趣。正向渗透（FO）膜因其各种优点而闻名，例如低能耗、性价比高、脱盐效率高以及污染最小。在此，使用分子动力学（MD）模拟研究了包含氮化硼狭缝膜（BNSM）的FO系统的脱盐性能。探讨了狭缝宽度、温度、汲取液（DS）浓度及其类型（MgCl、CaCl和KCl）等参数对盐离子截留率和水通量的影响。随着狭缝宽度从6 Å增加到9 Å，Na和Mg离子的截留率分别从100%降至94%和96%。此外，随着狭缝宽度的相同增加，水通量显著增加，从17.305增加到80.92分子/纳秒。温度升高导致离子截留率降低，水通量增加，因为根据斯托克斯-爱因斯坦方程，球形颗粒的扩散系数随温度升高而增加。由于狭缝宽度较小以及尺寸排阻的主导作用，DS浓度的变化对离子截留性能没有影响。DS浓度的增加导致浓度极化和渗透压降低，从而导致水通量下降。由于K离子的水合半径最大，Mg和Ca离子的截留率较高，而在CaCl和KCl作为DS的系统中，Na离子截留率分别具有最高和最低值，这与水通量的趋势一致。
