非溶剂致相分离法(NIPS)是一种成熟的制备聚合物多孔膜技术,但膜剥离时导致的相转化不均会对膜结构和性能产生影响。因此,以聚偏氟乙烯(PVDF)作为膜材料,以纯水为非溶剂进行延迟剥离实验。结果表明,通过延迟剥离的时间可以在保证BSA截留率维持在90%以上的情况下,有效提高PVDF超滤膜的纯水通量。延迟60min剥离的膜T5通量达到最高(412L/m2·h),较无延时操作的原始膜T0(351L/m2·h)提高了17.4%。此外,扫描电镜结果显示延迟剥离对膜形貌无显著影响,膜底部的孔隙相对更大。所以,作为一种简单、方便、低成本的方法,凝固浴延迟剥离可有效提高PVDF超滤膜的性能。
Non-solvent-induced phase separation (NIPS) is a well-established technique for the preparation of polymer porous membranes,but uneven phase conversion caused by membrane stripping can affect membrane structure and performance.In our work,polyvinylidene fluoride (PVDF) was used as the membrane material and pure water was used as the non-solvent for delayed stripping experiments.The results showed that the pure water flux of PVDF ultrafiltration membranes could be effectively improved by delaying the stripping time while maintaining the BSA retention rate of more than 90%.The highest T5 flux (412L·m-2·h-1) was achieved with a 60-minute delayed tripping,which was 17.4% higher that of the original membrane T0 (351L·m-2·h-1) without delayed operation.In addition,the SEM results indicated that the delayed stripping had no significant effect on the morphology of the membrane,and the pores at the bottom of the membrane were relatively larger.It provides a simple,convenient and low-cost method to improve the performance of PVDF ultrafiltration membranes.
[1] Pagliero M,Bottino A,Comite A,et al.Novel hydrophobic PVDF membranes prepared by nonsolvent induced phase separation for membrane distillation[J].Journal of Membrane Science,2020,596:117575.
[2] Kong X,Lu X L,Ren K.Towards high-performance polysulfone membranes:a controllable membrane formation process using surfactant in NIPS[J].Journal of the Taiwan Institute of Chemical Engineers,2021,129:171-179.
[3] Liu F,Tao M M,Xue L X.PVDF membranes with inter-connected pores prepared via a Nat-ips process[J].Desalination,2012,298:99-105.
[4] Yu H R,Shangguang S Y,Yang H Y,et al.Chemical cleaning and membrane aging of poly(vinylidene fluoride)(PVDF) membranes fabricated via non-solvent induced phase separation (NIPS) and thermally induced phase separation (TIPS)[J].Separation and Purification Technology,2023,313:123734.
[5] Yu Y,Wu Q Z,Yang G H,et al.Preparation of hydrophilic and antibacterial bifunctional PVDF ultrafiltration membrane based on pomegranate peel powder[J].Reactive and Functional Polymers,2024,197:105875.
[6] Tao M M,Liu F,Ma B R,et al.Effect of solvent power on PVDF membrane polymorphism during phase inversion[J].Desalination,2013,316:137-145.
[7] 徐小洁,于孟超,王钰,等.NIPS法疏水PVDF膜的结构与性能调控研究进展[J].膜科学与技术,2024,44(1):147-156.
[8] Lu K J,Liang C Z,Chen Y M L,et al.Unlock the secret of air blowing in developing high strength and superhydrophobic membranes for membrane distillation[J].Desalination,2022,527:115579.
[9] Xing X Y,Gu L,Jin Y,et al.Fabrication and characterization of cellulose triacetate porous membranes by combined nonsolvent-thermally induced phase separation[J].Cellulose,2019,26(6):3747-3762.
[10] Munirasu S,Banat F,Durrani A A,et al.Intrinsically superhydrophobic PVDF membrane by phase inversion for membrane distillation[J].Desalination,2017,417:77-86.
[11] Bottino A,Capannellig G,Comite A.Novel porous poly (vinylidene fluoride) membranes for membrane distillation[J].Desalination,2005,183(1-3):375-382.
[12] Tian M M,Yuan S S,Decaesstecker F,et al.One-step fabrication of isotropic poly(vinylidene fluoride) membranes for direct contact membrane distillation (DCMD)[J].Desalination,2020,477:114265.
[13] Zhang J G,Xu Z W,Mai W,et al.Improved hydrophilicity,permeability,antifouling and mechanical performance of PVDF composite ultrafiltration membranes tailored by oxidized low-dimensional carbon nanomaterials[J].Journal of Materials Chemistry A,2013,1(9):3101-3111.
[14] Liang J H,Tan Y,Yu Y,et al.Preparation of dopamine/Ag- modified graphene oxide/polysulfone/poly(vinylidene fluoride) ultrafiltration membrane with hydrophilic and antibacterial dual function[J].Polymers for Advanced Technologies,2023,34(5):1575-1584.
[15] Liao C J,Yu P,Zhao J Q,et al.Preparation and characterization of NaY/PVDF hybrid ultrafiltration membranes containing silver ions as antibacterial materials[J].Desalination,2011,272(1-3):59-65.
[16] Anvari A,Safekordi A,Hemmati M,et al.Enhanced separation performance of PVDF/PAN blend membrane based on PVP tuning[J].Desalination and Water Treatment,2015,57(26):12090-12098.
基金资助
湖南省教育厅重点项目(21A0129);湖南农业大学大学生创新训练项目(XCX2023114)
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