聚砜-聚酰胺正渗透复合膜的制备及性能优化

Preparation and Performance Optimizationof Polysulfonepolyamide Forward Osmosis Thin Film Membrane

采用相转化的方法制备聚砜支撑层,在其表面进行界面聚合得到聚砜-聚酰胺正渗透复合膜。系统研究了聚砜浓度、溶剂比例、支撑层厚度对膜性能的影响,并且优化了测试条件(如:膜面流速、错流方向、原料液温度以及驱动液浓度)。结果表明,在聚砜含量为w=12%、NMP与DMF质量比为3∶1、刮膜厚度为150μm、膜面流速为2.47 cm/s、反向错流方式下,聚砜-聚酰胺正渗透膜性能为:FO模式下,水通量为12.69 L/(m^2·h),反向盐通量为5.55 g/(m^2·h);PRO模式下,水通量为21.48 L/(m^2·h),反向盐通量为9.18 g/(m^2·h)。此外,原料液温度升高和驱动液浓度增加有利于提高膜的性能。正渗透复合膜的形貌和表面粗糙度通过SEM和AFM进行表征。

For the preparation of polysulfone-polyamide forward osmosis thin film membranes(TFC) ,the polysulfone support layer was fabricatedvia phase inversion method,and the polyamide rejection layer was prepared via interfacial polymerization on the polysulfone support layer.The influence of polysulfone concentration,solvent content,thickness andtest conditions(i.e.,flow rate,crossflow orientation,feed solution temperature,and draw solution concentration) on the performance of TFC membranes wassystematically investigated.The results showed the optimal condition was:polysulfone content was 12 wt%,NMP and DMF mass ratio was 3:1,membrane thickness was 150 μm,flow rate of surface membrane was 2.47 cm/s and reverse crossflow.In FO test,water flux of TFC membrane was 12.69 L/(m^2·h) and the reverse salt flux was 5.55 g/(m^2·h) .In PRO test,water flux of TFC membrane was 21.48 L/(m^2·h) and the reverse salt flux was 9.18 g/(m^2·h) .Moreover,the water flux was improved with the increase in feed solution temperature and draw solution concentration.The morphology and surface roughness ofmembrane were observed using field emission scanning electron microscope and atomic force microscopy.