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 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.

Induced Consumption of High-Concentration Ethanol Solution in Rats

1969 ◽  
Vol 30 (2) ◽  
pp. 330-335 ◽  
Author(s):  
R. J. Senter ◽  
Charles L. Richman
Keyword(s):  
Ethanol Solution ◽  
High Concentration

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 Direct visualization of virus removal process in hollow fiber membrane using an optical microscope

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Miku Ayano ◽  
Yoshiyuki Sawamura ◽  
Tomoko Hongo-Hirasaki ◽  
Takayuki Nishizaka
Keyword(s):  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Imaging Techniques ◽  
Basic Research ◽  
Optical Microscope ◽  
Regenerated Cellulose ◽  
Fiber Membrane ◽  
Virus Removal ◽  
Novel Method ◽  
Pass Through

AbstractVirus removal filters developed for the decontamination of small viruses from biotherapeutic products are widely used in basic research and critical step for drug production due to their long-established quality and robust performance. A variety of imaging techniques have been employed to elucidate the mechanism(s) by which viruses are effectively captured by filter membranes, but they are limited to ‘static’ imaging. Here, we propose a novel method for detailed monitoring of ‘dynamic process’ of virus capture; specifically, direct examination of biomolecules during filtration under an ultra-stable optical microscope. Samples were fluorescently labeled and infused into a single hollow fiber membrane comprising cuprammonium regenerated-cellulose (Planova 20N). While proteins were able to pass through the membrane, virus-like particles (VLP) accumulated stably in a defined region of the membrane. After injecting the small amount of sample into the fiber membrane, the real-time process of trapping VLP in the membrane was quantified beyond the diffraction limit. The method presented here serves as a preliminary basis for determining optimum filtration conditions, and provides new insights into the structure of novel fiber membranes.

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.

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.

Removal of high concentration Congo red by hydrophobic PVDF hollow fiber composite membrane coated with a loose and porous ZIF-71PVDF layer through vacuum membrane distillation

2020 ◽  
pp. 152808372096707
Author(s):  
Hongbin Li ◽  
Wenying Shi ◽  
Qiyun Du ◽  
Shoufa Huang ◽  
Haixia Zhang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Hollow Fiber ◽  
Congo Red ◽  
Fiber Composite ◽  
Water Flux ◽  
Membrane Distillation ◽  
Feed Flow Rate ◽  
High Concentration ◽  
Operation Conditions ◽  
Feed Temperature

Although membrane distillation (MD) technology has the outstanding advantages of almost 100% solute retention and mild operation conditions, its further development is limited by low permeate flux. In order to solve the problem, the improvement of membrane hydrophobicity becomes one of the effective solutions. In this study, a loose and porous hydrophobic zeolitic imidazolate frameworks-71 (ZIF-71)/polyvinylidene fluoride (PVDF) coating layer was composited on the outside surface of PVDF hollow fiber support membrane by the dilute solution coating to enhance membrane hydrophobicity. The prepared hollow fiber composite (HFC) membranes were employed to remove high concentration Congo red (CR) through VMD. The effects of different operation conditions including the dye concentration, feed temperature, vacuum pressure and feed flow rate on CR rejection and permeate water flux were investigated. In the variation range of operating conditions, all the CR rejection of the PVDF HFC membranes shows a slight change and remains above 99.9%. Under the optimal operation conditions including dye concentration 600 mg·L−1, vacuum pressure 31.325 kPa, feed temperature 60°C and feed flow rate 50 L·h−1, HFC membrane exhibit a permeate water flux of 13.15 kg·m−2·h−1. HFC membrane suffers dye fouling during the continuous dye filtration for 100 h. The fouling mechanism was proposed and a combined cleaning way including forward washing, back flushing and chemical desorption has been proved to be effective in recovering membrane water flux.

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