含有氨基化氧化石墨烯量子点中间层的反渗透膜的制备与性能研究

Preparation and performance of reverse osmosis membrane with amino-functionalized graphene oxide quantum dots interlayer

为了提高反渗透膜的分离性能,同时解决纳米材料在RO膜中分散性差、稳定性差的问题,首先在相转化法制备的聚砜(PSf)/聚酰亚胺(PI)共混超滤膜表面沉积氨基化氧化石墨烯量子点(af-GQDs)纳米材料制得af-GQDs中间层。af-GQDs表面的氨基通过共价键与基膜中的PI连接,使af-GQDs中间层更加牢固地与基膜结合在一起。同时,共价键作用有效改善了af-GQDs在基膜表面的分散性。随后,通过间苯二胺(MPD)与均苯三甲酰氯(TMC)的界面聚合反应在af-GQDs中间层表面构筑了聚酰胺分离层。在界面聚合的过程中,af-GQDs中间层通过氢键作用调控水相单体MPD向界面聚合反应区域中的扩散速率,进而提高了反渗透(RO)膜的分离性能。测试结果表明,最优的反渗透(RO)膜在1.0 MPa的操作条件下,对2 000 mg·L^(-1)NaCl溶液的水渗透率为20.9 L·m^(-2)·h^(-1)·MPa-1,NaCl截留率为98.9%。同时,所制备的含有af-GQDs中间层的反渗透膜具有较好的耐污染性能以及长期稳定性能。

In order to improve the separation performance of RO membranes,as well as overcome the poor dispersibility and stability of nanomaterials in RO membranes,in this work,the amino-functionalized graphene oxide quantum dots(af-GQDs)interlayer were constructed on the surface of polysulfone(PSf)/polyimide(PI)ultrafiltration membrane prepared via the phase inversion method.The af-GQDs interlayer was firmly bonded to the support membrane via the covalent bonding between amine groups of the af-GQDs and the PI contained in the support membrane.Meanwhile,the covalent bonding effectively improved the dispersion of af-GQDs on the surface of support membrane.Subsequently,a polyamide separation layer was constructed on the af-GQDs interlayer via the interfacial polymerization reaction between m-phenylenediamine(MPD)and trimesoyl chloride(TMC).In the process of interfacial polymerization,the af-GQDs interlayer could regulate the diffusion rate of aqueous phase monomer MPD into the interfacial polymerization reaction zone through hydrogen bonding,which could improve the separation performance of reverse osmosis(RO)membrane.The performance test results show that the best RO membrane(iTFC-10-0 RO)prepared under the optimal conditions have excellent water permeance of 20.9 L·m^(-2)·h^(-1)·MPa-1 and NaCl rejection of 98.9%for 2000 mg·L^(-1) NaCl solution at 1.0 MPa.In addition,the iTFC-10-0 RO membrane possessed excellent anti-fouling performance and long-time filtration stability performance.