基于多巴胺的杂化膜界面优化及其气体分离性能强化

Interfacial optimization of polymer-inorganic membranes for improved propylene dehumidification

采用仿生黏合剂多巴胺改性二氧化硅纳米颗粒(PDA@SiO2)并与聚乙烯醇(PVA)高分子基质共混,再将获得的PV A-PDA@SiO2杂化材料涂覆到聚砜(PSf)中空纤维支撑层表面制备中空纤维复合膜用于丙烯气体除湿,研究了杂化膜的微观形貌、晶态结构、高分子链运动性、自由体积特性等物理化学性质。实验结果表明,当填充剂PDA@SiO2含量(质量分数,下同)为1%时,在298 K、原料气水含量为0.5%的条件下,PV A-PDA@SiO2/PSf膜分离因子为24837,是PVA/PSf膜的12.7倍,渗透系数为904 GPU[1 GPU=7.501×10^-10 cm^3/(cm^2·s·Pa)],是PVA/PSf膜的3.6倍。仿生黏合剂多巴胺的多重相互作用可改善PVA与填充剂SiO2的界面相容性,进而提升杂化膜的分离性能。

A biomimetic binder,dopamine,has been used to form a coating of polydopamine(PDA)on silica nanoparticles.The modified nanoparticles were then incorporated in a poly(vinyl alcohol)(PVA)matrix which was subsequently used to prepare hybrid membranes by coating polysulfone(PSf)hollow fibers.The physicochemical properties of the resulting hybrid membranes,including crystallinity,glass transition temperature,and free volume properties were studied.When used for propylene gas dehumidification,the PVA-PDA@silica/PSf hybrid membranes exhibited the highest permeance of 904 GPU[1 GPU=7.501×10^-10 cm^3/(cm^2·s·Pa)](which is 3.6 times of that of a PVA/PSf membrane)when the PDA@silica content was 1 wt.%,and a separation factor of 24837(which is 12.7 times of that of a PVA/PSf membrane)with 0.5 wt.% water in the feed at 298 K.The results show that the multiple interactions of the bionic adhesive dopamine enhance the interfacial compatibility between the PVA polymer and the silica filler,resulting in the improved hybrid membrane separation performance.