The Effect of Temperature, Sulfonation, and PEG Addition on Physicochemical Characteristics of PVDF Membranes and Its Application on Hemodialysis Membrane

Polyvinylidene fluoride (PVDF) membrane and its derivative have been investigated the permeation ability for creatinine and urea. The membrane was made by an inversion precipitation system in N,N-dimethyl acetamide (DMAc) and water as non-solvents. In this study, the modification of PVDF membrane permeability with PEG additives, CBT variations, and sulfonation was successfully carried out. The membrane solidification process was carried out on three variations of the coagulation bath temperature (CBT): 30, 45, and 60 °C. Eight types of membranes were characterized by using FT-IR and TGA/DSC, followed by the analysis of their porosity, hydrophilicity, water uptake, swelling degree, tensile strength, and permeability of creatinine and urea. The FT-IR spectra indicate that PVDF modification has been successfully carried out. The porosity, hydrophilicity, water uptake, and swelling degree values increase with the modification of functional groups. Furthermore, improvements in creatinine and urea permeability and clearances are achieved by increasing CBT and sulfonation in the PVDF/PEG membrane. The presence of sulfonate groups improves the membrane permeability through the interaction of intermolecular hydrogen with water and dialysate compounds. The existence of PEG as a porogen enhanced membrane porosity. Creatinine and urea clearance values increase from 0.29–0.58 and 6.38–20.63 mg/dL, respectively.

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Characteristics and Preparation of PVDF Catalytic Membrane Modified by Nano-TiO2/Fe3+

The Open Materials Science Journal ◽

10.2174/1874088x01307010039 ◽

2013 ◽

Vol 7 (1) ◽

pp. 39-43

Author(s):

Xi Lijun ◽

Zhang Li ◽

Li Li ◽

Chi Jingyuan ◽

Lu Junchi ◽

...

Keyword(s):

Catalytic Activity ◽

Polyvinylidene Fluoride ◽

Sol Gel ◽

Water Flux ◽

Catalytic Membrane ◽

X Ray Diffraction ◽

Pvdf Membrane ◽

Tio2 Sol ◽

Ft Ir ◽

Good Filtration

The polyvinylidene fluoride (PVDF)/Fe3+-TiO2 catalytic membrane was prepared by sol-gel method. It was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), FT-IR spectrum (FT-IR), mechanics capability, water flux, pepsin retention, porosity and contact angle etc. The catalytic activity of PVDF/Fe3+-TiO2 catalytic membrane was evaluated by the degradation of refractory dye Orange IV in the presence of H2O2. The results show that the addition of appropriate nano-sized TiO2 sol in the preparation of PVDF membrane has greatly improved some properties of the membrane such as microstructure, hydrophilic ability, mechanics intensity and water flux etc. The addition of Fe3+ ion in the preparation of PVDF membrane has greatly improved its catalytic activity to decompose H2O2. The catalytic activity of PVDF/Fe3+ -TiO2 is increased with the increase of the content of Fe3+ ion. When the content of Fe3+ _TiO2 sol is 21%, the content of Fe3+ ion is from 0.02% to 0.12%, the discolorization rate of Orange IV in this Fenton-like oxidation is from 61.2% to 90.5%. The catalytic activity of PVDF/Fe3+-TiO2 is not changed with the increase of the content of nano-sized TiO2. This kind of PVDF/Fe3+ -TiO2 catalytic membrane has not only good filtration efficiency but also good catalytic activity to effectively decompose H2O2.

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Effect of temperature and salt on PVDF membrane wetting properties

Journal of Construction Materials ◽

10.36756/jcm.si1.2 ◽

2021 ◽

Author(s):

Kefan Jiang ◽

◽

Hooman Chamani ◽

Takeshi Matsuura ◽

Dipak Rana ◽

...

Keyword(s):

Contact Angle ◽

Polyvinylidene Fluoride ◽

Membrane Separation ◽

Feed Solution ◽

Membrane Distillation ◽

Effect Of Temperature ◽

Separation Processes ◽

Water Contact ◽

Pvdf Membrane ◽

Wetting Properties

Membrane distillation (MD) is a thermally driven separation process. Despite many advantages over other membrane separation processes, pore wetting hampers the wide commercial applications of the MD process. In this paper, the effect of temperature and presence (or absence) of salt in the feed solution on the wetting properties of commercial polyvinylidene fluoride (PVDF) membrane during a period of eight weeks was investigated. Liquid entry pressure (LEP) and water contact angle (WCA) were employed to characterize the wetting properties of the PVDF membrane. The result shows that the temperature has a significant impact on the decrease of the contact angle of the PVDF membrane.

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Membrane distillation crystallization using PVDF membrane incorporated with TiO2 nanoparticles and nanocellulose

Water Science & Technology Water Supply ◽

10.2166/ws.2020.068 ◽

2020 ◽

Vol 20 (5) ◽

pp. 1629-1642 ◽

Cited By ~ 1

Author(s):

Hoi-Fang Tan ◽

Why-Ling Tan ◽

N. Hamzah ◽

M. H. K. Ng ◽

B. S. Ooi ◽

...

Keyword(s):

Pore Size ◽

Tio2 Nanoparticles ◽

Polyvinylidene Fluoride ◽

Phase Inversion ◽

Membrane Distillation ◽

Coagulation Bath ◽

Membrane Thickness ◽

Permeate Flux ◽

Sem Images ◽

Pvdf Membrane

Abstract Polyvinylidene fluoride (PVDF) membrane was improved using TiO2 nanoparticles and nanocellulose for membrane distillation crystallization in this work. Besides the addition of TiO2 nanoparticles and nanocellulose, PVDF membrane was post-modified with octadecyltrichlorosilane after phase inversion using a dual coagulation bath. The addition of hydrophilic TiO2 nanoparticles and nanocellulose reduced membrane hydrophobicity, but the dispersed TiO2 nanoparticles assisted silane modification to improve surface hydrophobicity. Besides reducing the agglomeration of TiO2 nanoparticles, nanocellulose induced the formation of larger pore size and higher porosity as proven in SEM images and gravimetric measurement, respectively. The abundant moieties of nanocellulose accelerated the exchange between solvent and non-solvent during phase inversion for the formation of large pore size and porosity, but membrane thickness increased due to the thickening effects. The modified membrane showed higher water permeate flux in membrane distillation with salt rejection greater than 97%. Severe fouling in membrane distillation crystallization was not observed.

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Preparation and Characterization of a PVDF Membrane Modified by an Ionic Liquid

Australian Journal of Chemistry ◽

10.1071/ch18447 ◽

2019 ◽

Vol 72 (6) ◽

pp. 425 ◽

Cited By ~ 1

Author(s):

Pengzhi Bei ◽

Hongjing Liu ◽

Hui Yao ◽

Yang Jiao ◽

Yuanyuan Wang ◽

...

Keyword(s):

Ionic Liquid ◽

Pore Size ◽

Polyvinylidene Fluoride ◽

Membrane Surface ◽

Pvdf Membrane ◽

Force Microscopy ◽

Low Surface Energy ◽

Atomic Force ◽

Ft Ir ◽

Modified Membrane

In order to enhance the hydrophobicity of polyvinylidene fluoride (PVDF) porous membranes, the blending of PVDF with a hydrophobic ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) was carried out. The modified PVDF membranes with [Bmim][PF6] were fabricated through a non-solvent induced phase inversion using lithium chloride as a porogen in the PVDF casting solution. The effects of [Bmim][PF6] on the membrane characteristics were investigated. FT-IR analysis indicates that the IL is successfully retained by the PVDF membrane. Thermogravimetric analysis reveals that the optimum temperature of the modified membrane is below 300°C. Scanning electron microscopy pictures show that modified membranes have more homogeneous and larger diameter pores with a mean pore size of 0.521µm and porosity of 78%. By measuring the IL leaching during the membrane fabrication, it was found that the modified membrane does not lose IL. Atomic force microscopy shows that the roughness of the modified membrane surface increases slightly, but the contact angle of the modified membrane increases significantly from 88.1° to 110.1°. The reason for this is that the fluorine-containing IL has a low surface energy, which can enhance the hydrophobicity of the membrane. Finally, by comparing modified membranes with different IL concentrations, we draw a conclusion that the modified membrane with an IL concentration of 3 wt-% has the best properties of pore size, porosity, and hydrophobicity.

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Modification of the Surface Morphology and Properties of Graphene Oxide and Multi-Walled Carbon Nanotube-Based Polyvinylidene Fluoride Membranes According to Changes in Non-Solvent Temperature

Nanomaterials ◽

10.3390/nano11092269 ◽

2021 ◽

Vol 11 (9) ◽

pp. 2269

Author(s):

Jungryeong Chae ◽

Taeuk Lim ◽

Hao Cheng ◽

Wonsuk Jung

Keyword(s):

Graphene Oxide ◽

Functional Groups ◽

Polyvinylidene Fluoride ◽

Water Flux ◽

Bath Temperature ◽

Coagulation Bath ◽

Water Contact ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes ◽

Pure Pvdf

The effect of changes in non-solvent coagulation bath temperature on surface properties such as morphology and hydrophilicity were investigated in multi-walled carbon nanotubes (MWCNTs) and graphene oxide (GO)-based polyvinylidene fluoride (PVDF) membranes. The properties of pores (size, shape, and number) as well as membrane hydrophilicity were investigated using field emission scanning electron microscopy, Raman spectroscopy, optical microscopy, water contact angle, and water flux. Results showed that the pore size increased with an increase in coagulation temperature. The hydrophilic functional groups of the added carbon materials increased the solvent and non-solvent diffusion rate, which significantly increased the number of pores by 700% as compared to pure PVDF. Additionally, these functional groups changed the hydrophobic properties of pure PVDF into hydrophilic properties.

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Preparation of hydrophilic modified polyvinylidene fluoride (PVDF) ultrafiltration membranes by polymer/non-solvent co-induced phase separation: effect of coagulation bath temperature

Journal of Polymer Engineering ◽

10.1515/polyeng-2021-0245 ◽

2022 ◽

Vol 0 (0) ◽

Author(s):

Xiaoming Zhang ◽

Qingchen Lu ◽

Nana Li

Keyword(s):

Phase Separation ◽

Membrane Fouling ◽

Membrane Structure ◽

Polyvinylidene Fluoride ◽

Membrane Surface ◽

Pure Water ◽

Bath Temperature ◽

Coagulation Bath ◽

Separation Performance ◽

Coagulation Bath Temperature

Abstract Membrane separation technology is widely used in wastewater purification, but the issue of membrane fouling could not be ignored. Hydrophilic modification is an effective method to reduce membrane fouling. Therefore, in this work, a hydrophilic modified polyvinylidene fluoride (PVDF) ultrafiltration membrane was prepared by polymer/non-solvent co-induced phase separation, and the effect of coagulation bath temperature on the membrane structure and performance was systematically investigated based on the previous study. With the increased of the coagulation bath temperature, the phase separation process changed from delayed to instantaneous, and the membrane surface changed from porous to dense, while the macropore structures and sponge-like pores appeared on the cross-section. Meanwhile, the pure water flux decreased from 229.3 L/(m2·h) to 2.08 L/(m2·h), the protein rejection rate increased from 83.87% to 100%, and the surface water contact angle increased from 63° to 90°. Thus, excessively high coagulation bath temperature adversely affected the permeate and separation performance, as well as antifouling performance of the membrane. This study enriched the research for preparing separation membranes by polymer/non-solvent co-induced phase separation and provided a practical and theoretical reference for controlling the membrane structure and properties by changing the coagulation bath temperature.

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PHASE INVERSION PREPARATION AND MORPHOLOGICAL STUDY OF POLYVINYLIDENE FLUORIDE ULTRAFILTRATION MEMBRANE MODIFIED BY NANO-SIZED ALUMINA

Functional Materials Letters ◽

10.1142/s1793604709000648 ◽

2009 ◽

Vol 02 (03) ◽

pp. 113-119 ◽

Cited By ~ 3

Author(s):

A. M. BAZARGAN ◽

Z. GHOLAMVAND ◽

M. NAGHAVI ◽

M. R. SHAYEGH ◽

S. K. SADRNEZHAAD

Keyword(s):

Polyvinylidene Fluoride ◽

Phase Inversion ◽

Membrane Surface ◽

Bath Temperature ◽

Contact Angles ◽

Coagulation Bath ◽

Alumina Powder ◽

Effective Parameters ◽

Precipitation Bath ◽

Cross Sectional

In this study, polyvinylidene fluoride (PVDF) membranes with various structures ranging from dense to highly asymmetric morphologies were obtained by changing the effective parameters in the phase inversion process. The effect of some important processing parameters such as solution concentration, harshness of the precipitation bath, exposure time before immersion in coagulation bath and bath temperature was studied and the mentioned parameters were optimized. The membranes were then modified with nano-sized alumina powder in order to improve the hydrophilicity of the PVDF membranes. The surface morphology, surface and cross-sectional structures of the membranes were examined by scanning electron microscope (SEM) and atomic force microscope (AFM). The specific surface area of the membranes was determined using the Brunauer–Emmett–Teller (BET) method. The contact angles between water and the membranes' surfaces were measured in order to study the hydrophilicity changes of the membrane surface. The results indicated that the addition of nano-sized alumina to the casting dope increased the hydrophilicity of the PVDF membrane surface.

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Preparation and Electrochemical Characterization of Organic–Inorganic Hybrid Poly(Vinylidene Fluoride)-SiO2 Cation-Exchange Membranes by the Sol-Gel Method Using 3-Mercapto-Propyl-Triethoxyl-Silane

Materials ◽

10.3390/ma12193265 ◽

2019 ◽

Vol 12 (19) ◽

pp. 3265 ◽

Cited By ~ 1

Author(s):

Li ◽

Guan ◽

Zheng ◽

...

Keyword(s):

Membrane Potential ◽

Oxidative Stability ◽

Water Uptake ◽

Polyvinylidene Fluoride ◽

Vinylidene Fluoride ◽

Sol Gel ◽

Synthesis Method ◽

Co2 Production ◽

Inorganic Hybrid ◽

Poly Vinylidene Fluoride

A new synthesis method for organic–inorganic hybrid Poly(vinylidene fluoride)-SiO2 cation-change membranes (CEMs) is proposed. This method involves mixing tetraethyl orthosilicate (TEOS) and 3-mercapto-propyl-triethoxy-silane (MPTES) into a polyvinylidene fluoride (PVDF) sol-gel solution. The resulting slurry was used to prepare films, which were immersed in 0.01 M HCl, which caused hydrolysis and polycondensation between the MPTES and TEOS. The resulting Si-O-Si polymers chains intertwined and/or penetrated the PVDF skeleton, significantly improving the mechanical strength of the resulting hybrid PVDF-SiO2 CEMs. The -SH functional groups of MPTES oxidized to-SO3H, which contributed to the excellent permeability of these CEMs. The surface morphology, hybrid structure, oxidative stability, and physicochemical properties (IEC, water uptake, membrane resistance, membrane potential, transport number, and selective permittivity) of the CEMs obtained in this work were characterized using scanning electron microscope and Fourier transform infrared spectroscopy, as well as electrochemical testing. Tests to analyze the oxidative stability, water uptake, membrane potential, and selective permeability were also performed. Our organic–inorganic hybrid PVDF-SiO2 CEMs demonstrated higher oxidative stability and lower resistance than commercial Ionsep-HC-C membranes with a hydrocarbon structure. Thus, the synthesis method described in this work is very promising for the production of very efficient CEMs. In addition, the physical and electrochemical properties of the PVDF-SiO2 CEMs are comparable to the Ionsep-HC-C membranes. The electrolysis of the concentrated CoCl2 solution performed using PVDF-SiO2-6 and Ionsep-HC-C CEMs showed that at the same current density, Co2+ production, and current efficiency of the PVDF-SiO2-6 CEM membrane were slightly higher than those obtained using the Ionsep-HC-C membrane. Therefore, our novel membrane might be suitable for the recovery of cobalt from concentrated CoCl2 solutions.

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Influence of the Coagulation-Bath Temperature on Membrane Formation Mechanism and Properties of PVDF/TA-ATP Hybrid Membrane

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.713-715.2723 ◽

2015 ◽

Vol 713-715 ◽

pp. 2723-2726

Author(s):

Yue Rong Shi ◽

Gui Fang Zhang ◽

Xing Tian Liu ◽

Xue Tao Tian ◽

Yi Ping Zhao ◽

...

Keyword(s):

Formation Mechanism ◽

Vinylidene Fluoride ◽

Pure Water ◽

Water Flux ◽

Bath Temperature ◽

Time Domain Reflectometry ◽

Coagulation Bath ◽

Membrane Formation ◽

Water Permeation ◽

Ultrasonic Time

In this study, poly (vinylidene fluoride) (PVDF) hybrid membranes were prepared from polymeric blend of PVDF/tannic acid (TA)-Attapulgite (ATP)/PEG system via phase inversion induced by immersion precipitation in water coagulation bath. The membrane formation mechanism of PVDF/TA-ATP/PEG casting solutions in water bath thermodynamics at different temperatures and the process of membrane formation were investigated via cloud point determination and ultrasonic time-domain reflectometry (UTDR). The structures and properties of the membrane were characterized by scanning electron microscopy (SEM), and water permeation experiment, respectively. It was found that the rate of precipitation controlled by the Coagulation-Bath thermodynamics. With the coagulation temperature increasing, the gelation line was moved to non-solvent axis and the pure water flux were decreased.

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