CAJ | 학술논문

采用分子动力学模拟方法,探究了非常规双壁碳纳米管(DWCNT)在反渗透过程中,不同内外管间距对管道内水分子与盐离子运动行为的影响.本文采用0.5 mol?L-1氯化钠水溶液模拟海水,内管始终采用CNT(8,8)型,并对盐水层施加恒力模拟反渗透压.重点考察盐离子数量分布与通水情况,计算水分子平均力势,并分析水分子氢键寿命与偶极矩分布.结果表明,管间距不仅影响上述各项性质,还会改变盐离子与水分子在碳管中的渗透特性.模拟结果显示,小尺寸DWCNT可以有效实现盐水分离但水通量较小,大尺寸DWCNT的水容量较大但阻盐效率不高,而中尺寸DWCNT (即：管间距为0.815 nm)则具有最佳的通水阻盐性能.本文试图从分子层面揭示了DWCNT通水阻盐机理,并为人们设计新型海水淡化渗透膜提供理论指导.
채용분자동역학모의방법,탐구료비상규쌍벽탄납미관(DWCNT)재반삼투과정중,불동내외관간거대관도내수분자여염리자운동행위적영향.본문채용0.5 mol?L-1록화납수용액모의해수,내관시종채용CNT(8,8)형,병대염수층시가항력모의반삼투압.중점고찰염리자수량분포여통수정황,계산수분자평균력세,병분석수분자경건수명여우겁구분포.결과표명,관간거불부영향상술각항성질,환회개변염리자여수분자재탄관중적삼투특성.모의결과현시,소척촌DWCNT가이유효실현염수분리단수통량교소,대척촌DWCNT적수용량교대단조염효솔불고,이중척촌DWCNT (즉：관간거위0.815 nm)칙구유최가적통수조염성능.본문시도종분자층면게시료DWCNT통수조염궤리,병위인문설계신형해수담화삼투막제공이론지도.
Molecular dynamics simulation was used to study the effect of the outer-wal on water flux in the inner channel by varying the inter-layer spacing of unconventional double-wal ed carbon nanotube (DWCNT) under reverse-osmosis conditions. Salt rejection and the water transport behavior inside the DWCNT were also examined. In the simulation, 0.5 mol?L-1 NaCl aqueous solution was used to mimic seawater, and the chiral index of the inner-wal was fixed at (8, 8). A constant force on the salt solution produced pressure. Calculation of the number density profile of ions along the DWCNT axis showed that the water could be separated completely from the NaCl aqueous solution in some types of DWCNTs studied. Analyses of the hydrogen-bond lifetime, potential of mean force, and dipole moment distribution of the water molecules inside the DWCNT showed different permeabilities by water molecules and ions. An increase in the inter-layer spacing improved water flow in the DWCNT, which decreased the salt rejection performance. Final y, it was found that DWCNT with an inter-layer spacing of 0.815 nm gave the optimum balance between water flux and salt rejection. This study provides a molecular insight into the use of DWCNT in desalination, and wil enable the design of improved reverse-osmosis membranes with high performance in terms of salt rejection and water permeability.