scholarly journals Hydrophilic Dual Layer Hollow Fiber Membranes for Ultrafiltration

Membranes ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 143
Author(s):  
Lara Grünig ◽  
Ulrich A. Handge ◽  
Joachim Koll ◽  
Oliver Gronwald ◽  
Martin Weber ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Hollow Fiber ◽  
Triblock Copolymer ◽  
Pure Water ◽  
Vinyl Pyrrolidone ◽  
Scattering Data ◽  
Coupling Mechanism ◽  
Additive Concentration ◽  
Hollow Fiber Membranes ◽  
Fiber Membranes

In this study, a triblock copolymer was used as additive to fabricate new dual layer hollow fiber membranes with a hydrophilic active inner surface in order to improve their fouling resistance. The polymeric components of the solutions for membrane fabrication were poly(ether sulfone), poly(N-vinyl pyrrolidone), and the triblock copolymer. The additive consists of three blocks: a middle hydrophobic poly(ether sulfone) block and two outer hydrophilic alkyl poly(ethylene glycol) blocks. By varying the additive concentration in the solutions, it was possible to fabricate dual layer hollow fiber membranes that are characterized by a hydrophilic inner layer, a pure water permeance of over 1800 L/(m2 bar h) and a molecular weight cut-off of 100 kDa similar to commercial membranes. Contact angle and composition determination by XPS measurements revealed the hydrophilic character of the membranes, which improved with increasing additive concentration. Rheological, dynamic light scattering, transmission, and cloud point experiments elucidated the molecular interaction, precipitation, and spinning behavior of the solutions. The low-molecular weight additive reduces the solution viscosity and thus the average relaxation time. On the contrary, slow processes appear with increasing additive concentration in the scattering data. Furthermore, phase separation occurred at a lower non-solvent concentration and the precipitation time increased with increasing additive content. These effects revealed a coupling mechanism of the triblock copolymer with poly(N-vinyl pyrrolidone) in solution. The chosen process parameters as well as the additive solutions provide an easy and inexpensive way to create an antifouling protection layer in situ with established recipes of poly(ether sulfone) hollow fiber membranes. Therefore, the membranes are promising candidates for fast integration in the membrane industry.

Structure Morphology of Polyethersulfone Hollow Fiber Membrane via Immersion Precipitation Phase Inversion Process

2012 ◽  
Vol 152-154 ◽  
pp. 574-578 ◽  
Author(s):  
Ping Lan ◽  
Wei Wang
Keyword(s):  
Hollow Fiber ◽  
Phase Inversion ◽  
Hollow Fiber Membrane ◽  
Pure Water ◽  
Water Flux ◽  
Additive Concentration ◽  
Hollow Fiber Membranes ◽  
Fiber Membrane ◽  
Fiber Membranes ◽  
And Performance

Polyethersulfone (PES) hollow fiber membranes have been widely used in many fields, such as ultrafiltration, microfiltration, reverse osmosis, liquid/liquid or liquid/solid separation, gas separation, hemodialysis, and so on. In this paper, the sheet PES hollow fiber membranes were prepared. The morphology and performance of membranes can be controlled. By studying the influence of the compositions and conditions on the morphology and performance of PES hollow fiber membrane, the relationship of morphology and performance of the membrane is acquired. The additives were used such as glycerol, BuOH and PEG. In addition, immerse phase inversion was used as membranes preparation method. The morphology of the membrane was controlled by changing kinds of additive, concentration of additive and so on. It was found that the membrane morphologies were changed by additive obviously. Porosity , pure water flux, scanning electron microscopy(SEM) were used to characterize the morphology and performance of the membranes.

scholarly journals Structure and Properties of PSf Hollow Fiber Membranes with Different Molecular Weight Hyperbranched Polyester Using Pentaerythritol as Core

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 383
Author(s):  
Min Liu ◽  
Long-Bao Zhao ◽  
Li-Yun Yu ◽  
Yong-Ming Wei ◽  
Zhen-Liang Xu
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Hollow Fiber ◽  
Pure Water ◽  
Esterification Reaction ◽  
Hollow Fiber Membranes ◽  
Water Contact ◽  
Molecular Weights ◽  
Hyperbranched Polyesters ◽  
Fiber Membranes

A homologous series of hyperbranched polyesters (HBPEs) was successfully synthesized via an esterification reaction of 2,2-bis(methylol)propionic acid (bis-MPA) with pentaerythritol. The molecular weights of the HBPEs were 2160, 2660, 4150 and 5840 g/mol, respectively. These HBPEs were used as additives to prepare polysulfone (PSf) hollow fiber membranes via non-solvent induced phase separation. The characteristic behaviors of the casting solution were investigated, as well as the morphologies, hydrophilicity and mechanical properties of the PSf membranes. The results showed that the initial viscosities of the casting solutions were increased, and the shear-thinning phenomenon became increasingly obvious. The demixing rate first increased and then decreased when increasing the HBPE molecular weight, and the turning point was 2660 g/mol. The PSf hollow fiber membranes with different molecular weights of HBPEs had a co-existing morphology of double finger-like and sponge-like structures. The starting pure water contact angle decreased obviously, and the mechanical properties improved.

PVDF hollow fiber membranes prepared from green diluent via thermally induced phase separation: Effect of PVDF molecular weight

2014 ◽  
Vol 471 ◽  
pp. 237-246 ◽  
Author(s):  
Naser Tavajohi Hassankiadeh ◽  
Zhaoliang Cui ◽  
Ji Hoon Kim ◽  
Dong Won Shin ◽  
Aldo Sanguineti ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Phase Separation ◽  
Hollow Fiber ◽  
Thermally Induced Phase Separation ◽  
Hollow Fiber Membranes ◽  
Separation Effect ◽  
Thermally Induced ◽  
Fiber Membranes

Preparation for PTFE Hollow Fiber Membranes Used in Water Treatment and Optimization for its Extrusion Process

2013 ◽  
Vol 750-752 ◽  
pp. 828-831 ◽  
Author(s):  
Chao Zhuang ◽  
Zhi Qing Luo ◽  
Wen Qing Chen
Keyword(s):  
Water Treatment ◽  
Hollow Fiber ◽  
Retention Rate ◽  
Pure Water ◽  
Water Flux ◽  
Chemical Properties ◽  
Hollow Fiber Membranes ◽  
High Fracture ◽  
Processing Methods ◽  
Fiber Membranes

For their excellent physical and chemical properties, PTFE hollow fiber membranes can be used in harsh environment of water treatment. But the membranes cannot be prepared by conventional methods, such as the melting processing methods and the dry-wet spinning processing methods, because of a high melting point of 327°C and chemical stability. In this paper a method of extrusion-stretching-sintering is used, and using this method we get the membranes with high fracture strength (10MPa) and high pure water flux (1500L/(m2*h)), also the retention rate of bovine serum albumin reaching 50%, which meets the laboratory microfiltration membrane requirements.

scholarly journals Effect of Jet Stretch in the Fabrication of Polyethersulfone Hollow Fiber Spinning for Water Separation

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
N. Bolong ◽  
A. F. Ismail ◽  
M. R. Salim
Keyword(s):  
Hollow Fiber ◽  
Pure Water ◽  
Fiber Spinning ◽  
Hollow Fibers ◽  
Wet Spinning ◽  
Hollow Fiber Membranes ◽  
Water Separation ◽  
Water Permeation ◽  
Fiber Membranes ◽  
Ionic Solutes

The effect of jet stretch on the morphology, pure water permeation and sodium chloride rejection of hollow fiber membranes is analyzed by varying the spinning take up speed. Polyethersulfone hollow fibers were spun using dry–wet spinning technique. The membrane formulation of PES/NMP/Water/PVPk10 is spun at constant extrusion rate of 3.0 cm3/ min. The fiber take up speed during spinning varied from 19.7 to 29.5 cms–1, revealed that the flux of hollow fiber membranes is minimal when the fiber take up speed is equivalent to the velocity of dope extrusion. At low jet stretch, the permeability of membranes is high with elevated ionic solutes rejection produced. The influence of elongation stress towards hollow fiber membranes morphology and its performance for water separation is also highlighted.

Preparation and Characterization of Poly (vinylidene fluoride) Hollow Fiber Membranes via Modified Thermally Induced Phase Separation Process

2013 ◽  
Vol 734-737 ◽  
pp. 2172-2175 ◽  
Author(s):  
Ai Wen Qin ◽  
Xiang Li ◽  
Bo Mou Ma ◽  
Chun Yi Liu ◽  
Xin Zhen Zhao ◽  
...  
Keyword(s):  
Phase Separation ◽  
Hollow Fiber ◽  
Vinylidene Fluoride ◽  
Hollow Fiber Membrane ◽  
Pure Water ◽  
Thermally Induced Phase Separation ◽  
Hollow Fiber Membranes ◽  
Thermally Induced ◽  
Fiber Membranes ◽  
Poly Vinylidene Fluoride

Poly (vinylidene fluoride) (PVDF) hollow fiber membranes were successfully prepared using DMAc/γ-BL as the mixed diluent and PEG as the additive through modified thermally induced phase separation (M-TIPS) process. The membranes prepared were characterized by scanning electron microscope. Their properties such as water permeability and mechanical properties were also determined. The results show that PVDF membranes have spherical crystallites structure with interconnected network structure because of the combination of solidliquid and liquid-liquid phase separation. When using 25wt% aqueous ethanol solution as the coagulation, the PVDF hollow fiber membrane shows the tensile strength, i.e.4.59MPa and pure water flux, i.e.415 L/ (m2·h).

Preparation and Properties of Two-Dimensional Braid Heterogeneous-Reinforced Polyvinylidene Fluoride Hollow Fiber Membrane

2014 ◽  
Vol 936 ◽  
pp. 218-225 ◽  
Author(s):  
Quan Quan ◽  
Chang Fa Xiao ◽  
Hai Liang Liu ◽  
Wei Zhao ◽  
Xiao Yu Hu ◽  
...  
Keyword(s):  
Hollow Fiber ◽  
Polyvinylidene Fluoride ◽  
Polymer Solutions ◽  
Coating Layer ◽  
Pure Water ◽  
Water Flux ◽  
Two Dimensional ◽  
Hollow Fiber Membranes ◽  
Fiber Membranes ◽  
Pure Water Flux

The two-dimensional braid heterogeneous-reinforced (BHR) polyvinylidene fluoride (PVDF) hollow fiber membranes which include PVDF polymer solutions (coating layer) and the two-dimensional braid as a reinforcement were prepared through the dry-wet spinning process. The influence of PVDF concentration in polymer solutions on performance of BHR hollow fiber membranes were investigated by terms of pure water flux, protein rejection, a mechanical strength test, and morphology observations by a scanning electron microscope (SEM). The results of this study indicated that the tensile strength of the BHR PVDF hollow fiber membranes was nearly 75 MPa and the hollow fiber membranes were endowed with better flexibility performance. The BHR PVDF hollow fiber membranes had a favorable interfacial bonding between the coating layer and the two-dimensional braid. The pure water flux decreased, while the rejection ratio increased with the increase of polymer concentration.

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