Mitigating the hydraulic compression of nanofiltration hollow fiber membranes through a single-step direct spinning technique.
Most nanofiltration (NF) membranes have been made through complicated multistep or thin-film composite processes. They also suffer the compaction issue that reduces permeate flux in pressure-driven filtration processes. A single-step coextrusion hollow fiber fabrication technique via immiscibility induced phase separation (I(2)PS) process is presented in this study to fabricate NF hollow fiber membranes. A protective layer is concurrently formed on top of the selective layer during the phase inversion process. The fabricated hollow fiber membrane has a narrow pore size distribution with a molecular weight cutoff (MWCO) of 470 Da. The outer layer of the I(2)PS hollow fiber is found to serve as a buffering layer that mitigates hydraulic compression on the compaction of dense-selective layer and sublayer and helps to retain membrane performance during nanofiltration operations. The newly fabricated NF hollow fiber membrane exhibits an average pure water permeability of 3.2 L m(-2) h(-1) bar(-1) and shows good rejections toward the testing dyes. This study may offer a simple, direct, and cost-effective approach to fabricate NF hollow fiber membranes.
Department of Chemical & Biomolecular Engineering, National University of Singapore , 4 Engineering Drive 4, Singapore 117585, Singapore.
Yee Kang
YK
Ong
Tai-Shung
TS
Chung
D005374:Filtration / Q000295:instrumentation* / Q000379:methods; D008567:Membranes, Artificial; D049329:Nanostructures / Q000737:chemistry*; D010539:Permeability; D011312:Pressure; D018508:Water Purification
D008567:Membranes, Artificial