SWNT/PA薄层复合反渗透膜的分子动力学模拟研究  

Molecular dynamics simulation of SWNT/PA thin-layer composite reverse osmosis membrane

作　　者：陈赈 张俊[1] 刘璇[1] CHEN Zhen;ZHANG Jun;LIU Xuan(School of Engineering,Shanghai Ocean University,Shanghai 201306,China)

机构地区：[1]上海海洋大学工程学院,上海201306

出　　处：《膜科学与技术》2025年第2期92-99,共8页Membrane Science and Technology

摘　　要：采用分子动力学方法,设计了一种新型的单壁碳纳米管(SWNT)/聚酰胺(PA)薄层复合(TFC)反渗透(RO)膜结构,并建立相应模型开展复合膜水渗透系数及反渗透截盐机理研究。首先,建立PA膜模型,分析了膜厚度对水渗透系数的影响,发现水渗透系数随着膜厚度下降而增加的规律;同时,进行PA膜溶胀模拟测试,确定聚合物交联度(DPC)为83%时PA膜最为稳定。在此基础上,建立了SWNT/PA膜模型,并采用其对初始浓度为0.25 mol/L的混合盐水进行过滤测试,发现复合膜在保留高截留率的同时,水渗透系数可增至70.391 L/(m^(2)·h·MPa),是PA膜的1.5倍。复合膜性能的提升可归因于SWNT的掺杂不仅扩大了PA膜孔隙,而且增加了水分子传输通道。本研究从微观层面揭示了PA TFC反渗透膜的反渗透机理为尺寸筛分效应,为合理设计高性能复合反渗透膜提供了有益的理论参考。A novel single-walled carbon nanotube(SWNT)/polyamide(PA)thin-layer composite(TFC)reverse osmosis(RO)membrane structure was designed by molecular dynamics method,and the corresponding model was established to study the water permeability coefficient of the composite membrane and the mechanism of reverse osmosis salt interception.Firstly,the PA membrane model was established,and the influence of membrane thickness on water permeability coefficient was analyzed.It was found that the water permeability coefficient increased with the decrease of membrane thickness.At the same time,the swelling simulation test of PA membrane was carried out,and it was determined that the PA membrane was the most stable when the crosslinking degree(DPC)of the polymer was 83%.On this basis,the SWNT/PA membrane model was established and used to filter the mixed brine with an initial concentration of 0.25 mol/L.It was found that the water permeability coefficient of the composite membrane could be increased to 70.391 L/(m 2·h·MPa)while retaining the high rejection rate,which was 1.5 times that of the PA membrane.The improvement of the performance of the composite membrane can be attributed to the fact that the doping of SWNT not only expands the pores of the PA membrane,but also increases the water molecule transport channel.This study reveals that the salt rejection mechanism of PA TFC reverse osmosis membrane is size sieving effect from the micro level,which provides a useful theoretical reference for the rational design of high-performance composite reverse osmosis membranes.

关 键 词：聚酰胺 反渗透 分子动力学模拟 碳纳米管 

分 类 号：TQ019[化学工程]