scholarly journals Spinning Cellulose Hollow Fibers Using 1-Ethyl-3-methylimidazolium Acetate–Dimethylsulfoxide Co-Solvent

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 972 ◽  
Author(s):  
Linfeng Lei ◽  
Arne Lindbråthen ◽  
Marius Sandru ◽  
Maria Gutierrez ◽  
Xiangping Zhang ◽  
...  
Keyword(s):  
Hollow Fiber ◽  
Average Diameter ◽  
Hollow Fibers ◽  
Cellulose Ii ◽  
Cellulose I ◽  
Structure Transition ◽  
Carbon Membranes ◽  
Ftir Characterization ◽  
Dope Solution ◽  
Mild Temperature

The mixture of the ionic liquid 1-ethyl-3-methylimidazolium acetate (EmimAc) and dimethylsulfoxide (DMSO) was employed to dissolve microcrystalline cellulose (MCC). A 10 wt % cellulose dope solution was prepared for spinning cellulose hollow fibers (CHFs) under a mild temperature of 50 °C by a dry–wet spinning method. The defect-free CHFs were obtained with an average diameter and thickness of 270 and 38 µm, respectively. Both the XRD and FTIR characterization confirmed that a crystalline structure transition from cellulose I (MCC) to cellulose II (regenerated CHFs) occurred during the cellulose dissolution in ionic liquids and spinning processes. The thermogravimetric analysis (TGA) indicated that regenerated CHFs presented a similar pyrolysis behavior with deacetylated cellulose acetate during pyrolysis process. This study provided a suitable way to directly fabricate hollow fiber carbon membranes using cellulose hollow fiber precursors spun from cellulose/(EmimAc + DMSO)/H2O ternary system.

scholarly journals Optimization of Deacetylation Process for Regenerated Cellulose Hollow Fiber Membranes

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Xuezhong He
Keyword(s):  
Reaction Time ◽  
Hollow Fiber ◽  
Ethanol Solution ◽  
Hollow Fibers ◽  
Orthogonal Experimental Design ◽  
Regenerated Cellulose ◽  
High Concentration ◽  
Carbon Membranes ◽  
Tertiary Amide ◽  
Acetyl Content

Cellulose acetate (CA) hollow fibers were spun from a CA+ Polyvinylpyrrolidone (PVP)/N-methyl-2-pyrrolidone (NMP)/H2O dope solution and regenerated by deacetylation. The complete deacetylation time of 0.5 h was found at a high concentration (0.2 M) NaOH ethanol (96%) solution. The reaction rate of deacetylation with 0.5 M NaOH was faster in a 50% ethanol compared to a 96 vol.% ethanol. The hydrogen bond between CA and tertiary amide group of PVP was confirmed. The deacetylation parameters of NaOH concentration, reaction time, swelling time, and solution were investigated by orthogonal experimental design (OED) method. The degree of cross-linking, the residual acetyl content, and the PVP content in the deacetylated membranes were determined by FTIR analysis. The conjoint analysis in the Statistical Product and Service Solutions (SPSS) software was used to analyze the OED results, and the importance of the deacetylation parameters was sorted as Solution > Swelling time > Reaction time > Concentration. The optimal deacetylation condition of 96 vol.% ethanol solution, swelling time 24 h, the concentration of NaOH (0.075 M), and the reaction time (2 h) were identified. The regenerated cellulose hollow fibers under the optimal deacetylation condition can be further used as precursors for preparation of hollow fiber carbon membranes.

scholarly journals Hollow Fiber Membranes of Blends of Polyethersulfone and Sulfonated Polymers

Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 54 ◽  
Author(s):  
Nazia Noor ◽  
Joachim Koll ◽  
Nico Scharnagl ◽  
Clarissa Abetz ◽  
Volker Abetz
Keyword(s):  
Hollow Fiber ◽  
Photoelectron Spectroscopy ◽  
Membrane Surface ◽  
Water Flux ◽  
Hollow Fibers ◽  
Hollow Fiber Membranes ◽  
Water Permeation ◽  
Additive System ◽  
Fiber Membranes ◽  
Dope Solution

Hollow fiber membranes (HFM) are fabricated from blend solutions of a polyethersulfone (PESU) with a sulfonated PESU (sPESU) or a sulfonated polyphenylenesulfone (sPPSU). The influence of different additives in the dope solution and different bore fluids on the HFM are studied. The addition of poly(sodium 4-styrene sulfonate) (PSSNa)/ethylene glycol (EG) to the dope solution results in an increased water flux of the HFM compared to its counterparts without this additive system. The morphology of the hollow fibers is examined by scanning electron microscopy (SEM). The inner surface of the hollow fibers is studied by X-ray photoelectron spectroscopy (XPS), and it is found that water permeation through the hollow fiber membranes is facilitated due to the change in morphology upon the addition of the PSSNa/EG additive system, but not by the presence of hydrophilic sulfonic acid groups on the membrane surface.

Enterovirus Concentration Using Automated Hollow Fiber Ultrafiltration

1982 ◽  
Vol 14 (4-5) ◽  
pp. 257-272 ◽  
Author(s):  
G Belfort ◽  
A Paluszek ◽  
L S Sturman
Keyword(s):  
Drinking Water ◽  
Hollow Fiber ◽  
Enhanced Recovery ◽  
Tap Water ◽  
Membrane Surface ◽  
Creeping Flow ◽  
Hollow Fibers ◽  
Virus Concentration ◽  
Concentration Technique ◽  
Solution Interface

The Automated Hollow Fiber Ultrafiltration (AHFU) method is proposed here as a simple, efficient and rapid virus concentration technique from tap and drinking water sources. The results reported here extend the testing of the AHFU method to include two Picornaviruses [Poliovirus 2 (vaccine) and Echovirus 1] and Reovirus 3. Their respective mean virus recoveries from between 3 and 100 l of tap water is 88 ± 26, 79 ± 60, and 104 ± 48%. Various approaches including membrane surface modification, changes in backwash hydrodynamics, modification of the feed and backwash composition, and the use of S35-methionine labelled Poliovirus 2, are used to study the recovery of sorbed Poliovirus 2 from the hollow fiber/solution interface. An increase in the backwash pH to between 9.5 and 10.5 significantly improved Poliovirus 2 recovery. This, together with the labelled experiments, indicates that the virus-membrane interactions are probably electrostatic in nature. Convective polarization during filtration probably brings the virus close enough to the surface for these interactions to occur since virus losses were not detected for a non-permeation recycle experiment. Because very low Reynold's numbers are used, the flow is in the creeping-flow-regime for both filtration and backwashing (axial and radial). Unless significantly higher Reynolds could be used, enhanced recovery due to purely hydrodynamic forces is unlikely. High Reynold's numbers, of course, are limited by the pressure constraints of the hollow fibers.

scholarly journals Stable, metastable and unstable cellulose solutions

2017 ◽  
Vol 4 (8) ◽  
pp. 170487 ◽  
Author(s):  
Marta Gubitosi ◽  
Pegah Nosrati ◽  
Mona Koder Hamid ◽  
Stefan Kuczera ◽  
Manja A. Behrens ◽  
...  
Keyword(s):  
Microcrystalline Cellulose ◽  
Small Angle ◽  
Supersaturated Solution ◽  
Cellulose Ii ◽  
Cellulose I ◽  
Tetrabutylammonium Hydroxide ◽  
X Ray ◽  
Stable Regime ◽  
X Ray Scattering ◽  
A Minor

We have characterized the dissolution state of microcrystalline cellulose (MCC) in aqueous tetrabutylammonium hydroxide, TBAH(aq), at different concentrations of TBAH, by means of turbidity and small-angle X-ray scattering. The solubility of cellulose increases with increasing TBAH concentration, which is consistent with solubilization driven by neutralization. When comparing the two polymorphs, the solubility of cellulose I is higher than that of cellulose II. This has the consequence that the dissolution of MCC (cellulose I) may create a supersaturated solution with respect to cellulose II. As for the dissolution state of cellulose, we identify three different regimes. (i) In the stable regime, corresponding to concentrations below the solubility of cellulose II, cellulose is molecularly dissolved and the solutions are thermodynamically stable. (ii) In the metastable regime, corresponding to lower supersaturations with respect to cellulose II, a minor aggregation of cellulose occurs and the solutions are kinetically stable. (iii) In the unstable regime, corresponding to larger supersaturations, there is macroscopic precipitation of cellulose II from solution. Finally, we also discuss strong alkali solvents in general and compare TBAH(aq) with the classical NaOH(aq) solvent.

scholarly journals Polymeric Hollow Fibers: State of the Art Review of Their Preparation, Characterization and Applications in Different Research Areas

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
K.C. Khulbe ◽  
C. Feng ◽  
T. Matsuura ◽  
M. Khayet
Keyword(s):  
Hollow Fiber ◽  
Manufacturing Industry ◽  
Hollow Fiber Membrane ◽  
Waste Water Treatment ◽  
Hollow Fibers ◽  
Hollow Fiber Membranes ◽  
Seawater Desalination ◽  
Fiber Morphology ◽  
Fiber Technology ◽  
Fiber Membranes

In this article an attempt is made to review critically the papers published recently on polymeric hollow fibers and hollow fiber membranes. Hollow fiber membranes emerged in early nineteen sixties at almost the same time as the announcement of the cellulose acetate reverse osmosis membrane for seawater desalination by Loeb and Sourirajan. Since then, the hollow fiber technology has progressed along with the industrial membrane separation processes. Today, hollow fiber membranes are being used in every sector of the manufacturing industry, including gas and vapor separation, seawater desalination and waste water treatment. The fabrication of a hollow fiber membrane with a desirable pore–size distribution and performance is not an easy task. There are many factors controlling fiber morphology during the phase inversion process and, at present, we are not able to say that we fully understand the phenomena involved in the fabrication of hollow fibers. Nevertheless, there has been a large amount of knowledge accumulated during the past fifteen years, which has been supported by an equally large amount of efforts by many researchers. This paper attempts to summarize those works. The authors could however look into only those reports which have appeared in scientific journals and few patents, and they are fully aware that there must be much more information that has not surfaced to the journal publication. It is also the authors’ intention to show the future direction including the research topics that have been studied only little or not at all.

Eco-Friendly Preparation of Nanofibrillated Cellulose from Water Hyacinth Using NaOH/Urea Pretreatment

2020 ◽  
Vol 990 ◽  
pp. 225-230
Author(s):  
Kraiwit Pakutsah ◽  
Duangdao Aht-Ong
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Water Hyacinth ◽  
Aqueous Suspension ◽  
Nanofibrillated Cellulose ◽  
Cellulose Ii ◽  
Cellulose I ◽  
X Ray ◽  
Transmission Electron ◽  
Water Hyacinth Fiber

In this work, we described an effective approach to prepare nanofibrillated cellulose (NFC) with cellulose II structure under mild condition. Firstly, the water hyacinth (WH) was subjected to a series of a two-step chemical treatment, NaOH/urea pretreatment, and mechanical defibrillation at different defibrillation times. After that, raw water hyacinth fiber (RWF), bleached water hyacinth fiber (BWF), NaOH/urea pretreated water hyacinth fiber (PWF), and the resulting NFC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) as well as rheological measurements. It was found that RWF and BWF exhibited cellulose I crystal structure, whereas PWF and the obtained NFC possessed cellulose II crystal structure. FTIR analysis confirmed the evidence that no other chemical reactions preferentially occurred during both NaOH/urea pretreatment and mechanical defibrillation. As evidenced by rheological properties analysis, the NFC aqueous suspension with a gel-like structure demonstrated a shear-thinning behavior. The obtained NFC could potentially be utilized as a reinforcement for polymeric composites.

Microstructure and Mechanical Behavior of CaCu3Ti4O12 Ceramics Hollow Fiber Prepared via Dry/Wet Spinning Method

2020 ◽  
Vol 1010 ◽  
pp. 239-243
Author(s):  
Mohsen Ahmadipour ◽  
Tunmise Ayode Otitoju ◽  
Mohammad Arjmand ◽  
Zainal Arifin Ahmad ◽  
Swee Yong Pung
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Hollow Fiber ◽  
Outer Layer ◽  
Pore Diameter ◽  
Hollow Fibers ◽  
Wet Spinning ◽  
Outer Diameter ◽  
Average Pore ◽  
Elongation At Break

Dry/wet method was used to prepare CaCuTi4O12 (CCTO) hollow fibers (HFs) and then the structural and physico-mechanical properties of HFs were characterized by XRD, FESEM, BET and tensile strength, respectively. The outer diameter and thickness of CCTO HFs were found to be 650 μm and 390 μm, respectively. A finger-like macrovoids and sponge-like was observed inside the membrane with a denser structure in the outer layer. It was observed that the crystallite size was increased from 28.5 nm to 37.0 nm while the average pore diameter was decreased from 34.65 nm to 29.16 nm in CCTO hollow fiber with 1.0 wt.% CCTO. In addition, the tensile strength of HFS was significantly improved from 4.84 MPa to 5.54 MPa and elongation at break was decreased from 6.97 % to 5.09 % which is ascribed to the reduction in porosity. All the results indicated the significant effect of CCTO content on properties of CCTO hollow fibers. The finding in this study could lead to a new direction to enhance the properties of HFS with potential application in membranes.

scholarly journals Temperature Coagulant Tub Variation Effect on the Characteristic of Hollow Fiber Dialyser from Cellulose Acetate Composite D-Glucose Monohydrate

2017 ◽  
Vol 31 ◽  
pp. 53-60
Author(s):  
Rizki Firsta Wahyuliswari ◽  
Siswanto ◽  
Prihartini Widiyanti
Keyword(s):  
Tensile Strength ◽  
Creatinine Clearance ◽  
Cellulose Acetate ◽  
Hollow Fiber ◽  
Bath Temperature ◽  
Hollow Fibers ◽  
Coagulation Bath ◽  
Temperature Variations ◽  
Swelling Rate ◽  
Coagulation Bath Temperature

Polysulfone is synthetic polymer widely used as basic material for dialyzer membrane and hydrophobic so it tends to cause fouling. Cellulose acetate is non-synthetic, hydrophilic polymer which has low tendency of fouling and has good thermal stability and permeability so it is considered as alternative material for hollow fiber dialyzer. A proper hollow fiber can be achieved by setting a proper temperature of coagulation bath along the spinning process. This research aims to understand the effect of coagulation bath temperature variations on the physical characteristic such as pore size, tensile strength, swelling rate and creatinine clearance of cellulose acetate – D-glucose monohydrate hollow fibers. Hollow fibers were fabricated using spinneret at temperature variations 5°C, 10°C, 15°C dan 20°C. Physical characteristics were estimated by doing morphology test using SEM, tensile test, swelling test towards Simulated Body Fluid (SBF) and filtration test towards creatinine. Result revealed that the hollow fibers from 5°C coagulation bath temperature gives the best characteristic and performance with tensile strength 27,421 N mm-2, pore size 0,0295–0,0858 nm, swelling rate 4,18%, elongation rate 4,4 %, flux rate 1,6032–1,7956 mL cm-2 min-1 and creatinine clearance rate 40,14–48,30% so it is potential to be applied as dialyzer membrane.

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