Hollow fiber ultrafiltration membranes with microstructured inner skin

2011-03-01
Çulfaz Emecen, Pınar Zeynep
Lammertink, R.G.H.
Hollow fiber membranes with microstructured inner surfaces were fabricated from a PES/PVP blend using a spinneret with a microstructured needle. The effect of spinning parameters such as polymer dope flow rate, bore liquid flowrate, air gap and take-up speed on the microstructure and shape of the bore and its deformation was investigated. It was found that when a high bore liquid flowrate was used, the microstructure in the bore surface was destroyed. The bores were deformed to an oval shape when the fiber walls were thick. This was attributed to buckling of the fiber shell as a result of the coagulation and shrinkage of the outer surface. Fibers were also fabricated with a round-needled spinneret for comparison. The intrinsic pure water permeabilities (based on the actual bore surface areas) of fibers with structured and round bores were found to be similar. On the other hand, the structured fibers have larger pores in the skin layer. Smaller pores on the round fibers are considered to form when the inner surface coagulates and the skin layer is pulled inwards due to the shrinkage caused by phase separation. When the bore is structured, the wavy shape can damp this contraction effect resulting in larger pores. The skin layer thickness of the fibers was investigated using a colloidal filtration method. It was shown that fibers with microstructured bores which have mostly uniform skin layer thickness and reasonably narrow pore size distribution can be fabricated.
Journal of Membrane Science

Suggestions

Microstructured hollow fibers for ultrafiltration
Çulfaz Emecen, Pınar Zeynep; Van Rijn, Cees; Lammertink, Rob G.H.; Wessling, Matthias (2010-02-01)
Hollow fiber ultrafiltration membranes with a corrugated outer microstructure were prepared from a PES/PVP blend. The effect of spinning parameters such as air gap, take-up speed, polymer dope viscosity and coagulation value on the microstructure and membrane characteristics was investigated. Fibers with maximum 89% surface area enhancement were prepared. The structured fibers and the round fibers spun under the same conditions had comparable (intrinsic) pure water permeability, molecular weight cut-off, po...
Fabrication of polyethersulfone hollow fibers for ultrafiltration
Kaltalı, Gülçin; Çulfaz Emecen, Pınar Zeynep; Kalıpçılar, Halil; Department of Chemical Engineering (2014)
Hollow fiber membranes take an important part in membrane separation processes. They are used in many areas like gas separation, pervaporation, ultrafiltration and microfiltration processes due to their advantages like high membrane area per volume and easy backwashability. Poly(ethersulfone) (PES) is one of the most commonly used polymers in preparing hollow fiber ultrafiltration membranes. Due to its hydrophobic character, use of hydrophilic additives is usually necessary to make membranes resistant to fo...
Metal-assisted nano-textured solar cells with SiO2/Si3N4 passivation
Es, Fırat; Baytemir, Gulsen; Kulakci, Mustafa; Turan, Raşit (2017-02-01)
We demonstrate the fabrication of nano-sized surface textured crystalline silicon by a metal-assisted electroless etching method with nitric acid added as the hole injection agent. This method generates randomly shaped cone-like structures that offer a clear advantage over nanowires by enabling straightforward passivation with standard techniques. Average reflection values as low as 3% have been achieved. Optimizing the thickness of anti-reflective coatings, the doping depth and the screen-printed metal fir...
Helical hollow fibers via rope coiling: Effect of spinning conditions on geometry and membrane morphology
Yucel, Hazal; Çulfaz Emecen, Pınar Zeynep (Elsevier BV, 2018-08-01)
Helical hollow fiber membranes from poly(ether sulfone) were spun via dry-wet spinning, making use of the liquid rope coiling phenomenon. The polymer solution composition was changed by varying the coagulation value and adding PEG400 as pore former. The bore liquid composition, outer coagulation bath temperature, air gap, polymer dope and bore liquid flowrates were varied to map the conditions where helical fibers form. It was observed that increasing air gap changed fiber geometry from straight to helical....
NMR ANALYSIS AND MODELING OF SHRINKAGE AND WHEY EXPULSION IN RENNET CURD
OZILGEN, M; KAUTEN, RJ (1994-01-01)
The displacement of the curd surface after cutting and the profiles of residual water entrapped inside were monitored using one dimensional magnetic resonance imaging (MRI). Shrinkage of the curd occurred in two phases: the curd shrank immediately during cutting and then continued shrinking at a lower velocity. Experimental data of the one dimensional shrinkage of the curd obtained from the literature were simulated with a logistic equation. NMR analysis and literature data showed that the shrinkage velocit...
Citation Formats
P. Z. Çulfaz Emecen and R. G. H. Lammertink, “Hollow fiber ultrafiltration membranes with microstructured inner skin,” Journal of Membrane Science, pp. 221–227, 2011, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/33154.