Studies on the Relationship between Morphology and Water Flux of PVDF/PU Blend Membranes

2011 ◽  
Vol 121-126 ◽  
pp. 387-391
Author(s):  
Guo Lan Huan ◽  
Jian Li Liu ◽  
Qi Yun Du ◽  
Xiao Yu Hu
Keyword(s):  
Cross Section ◽  
Polyvinylidene Fluoride ◽  
Fractal Theory ◽  
Membrane Surface ◽  
Water Flux ◽  
Precipitation Process ◽  
Blend Membrane ◽  
Blend Membranes ◽  
Operation Pressure ◽  
The Relationship

Polyvinylidene fluoride/polyurethane (PVDF/PU) blend membranes were made via immersion precipitation process, the surface morphologies and the micro-porous structures of the blend membranes were analyzed using scanning electronic microscope (SEM) and fractal theory, the water flux change with the operation pressure of the blend membranes was investigated, and the relationship between blend membrane morphology and water flux was discussed. The results showed that, the water flux of the resulting blend membranes was increased, and the contribution of different structures to water flux was in the following order: cross-section finger-shaped porous defects > cross-section through holes > blend membrane surface pores. In addition, water flux of the blend membranes was also related to the deformability of PU.

scholarly journals Fabrication and Characterization of Nanofibers Membranes using Electrospinning Technology for Oil Removal

2021 ◽  
Vol 18 (4) ◽  
pp. 1338
Author(s):  
Amer Naji Al-Naemi ◽  
Mohammed Amer Abdul-Majeed ◽  
Mustafa H. Al-Furaiji ◽  
Inmar N Ghazi
Keyword(s):  
Polyvinylidene Fluoride ◽  
Membrane Surface ◽  
Water Flux ◽  
Oil Removal ◽  
Nanofiber Membrane ◽  
Pvdf Membrane ◽  
Electrospinning Method ◽  
Average Water ◽  
Graphene Membranes

Oily wastewater is one of the most challenging streams to deal with especially if the oil exists in emulsified form. In this study, electrospinning method was used to prepare nanofiberous polyvinylidene fluoride (PVDF) membranes and study their performance in oil removal. Graphene particles were embedded in the electrospun PVDF membrane to enhance the efficiency of the membranes. The prepared membranes were characterized using a scanning electron microscopy (SEM) to verify the graphene stabilization on the surface of the membrane homogeneously; while FTIR was used to detect the functional groups on the membrane surface. The membrane wettability was assessed by measuring the contact angle. The PVDF and PVDF / Graphene membranes efficiency was tested in separation of emulsified oil from aqueous solutions. The results showed that PVDF-Graphene nanofiber membrane exhibited better performance than the plain PVDF nanofiber membrane with average water flux of 210 and 180 L.m-2.h-1, respectively. Both membranes showed high oil rejection with more than 98%.

Effects of polymer blend composition on membrane properties and separation performance of PEES/PEI blend membrane

2016 ◽  
Vol 29 (4) ◽  
pp. 467-475 ◽  
Author(s):  
R Saranya ◽  
JS Beril ◽  
D Mohan
Keyword(s):  
Thermal Stability ◽  
Contact Angle ◽  
Protein Separation ◽  
Pure Water ◽  
Water Flux ◽  
Membrane Properties ◽  
Separation Performance ◽  
Blend Membrane ◽  
Blend Membranes ◽  
Protein Rejection

In this work, an attempt has been made for protein rejection from aqueous solution using ultrafiltration blend membrane based on poly(phenylene ether ether sulfone) (PEES) and polyetherimide (PEI) was prepared in various blend compositions. Prepared membranes were characterized in terms of pure water flux, water content, membrane hydraulic resistance, porosity, contact angle, scanning electron microscopy, thermogravimetric analysis, and attenuated total reflectance-Fourier transform infrared spectroscopy. Studies were carried out to find out the rejection of proteins such as trypsin, pepsin, egg albumin, and bovine serum albumin. The extent of protein separation is directly proportional to molecular weight of protein. Pristine PEES membrane exhibited high-percentage protein rejection of BSA (92.7%), EA (88.2%), pepsin (85.8%), and trypsin (82.2%) compared to PEES/PEI blend membranes. PEES/PEI blend membranes have better hydrophilic property compared to pristine PEES membrane. Pristine PEES has a contact angle of 97.8°, embedded with PEI and reduced to 67.9°. The thermal stability of the membrane was slightly decreased when the percentage of PEI composition into the PEES/PEI blend increased and observed that the pure PEES membrane has superior thermal stability than PEES/PEI blend membranes

Effect of the molecular weight and its distribution of polyvinylidene fluoride on the relationship between the spinning process, microstructure and properties of hollow fiber membranes via thermally induced phase separation

2018 ◽  
Vol 89 (7) ◽  
pp. 1311-1320 ◽  
Author(s):  
Nana Li ◽  
Zhe Chang ◽  
Qingchen Lu ◽  
Changfa Xiao ◽  
Junyi Wu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Phase Separation ◽  
Polyvinylidene Fluoride ◽  
Crystallization Behavior ◽  
Water Flux ◽  
Thermally Induced Phase Separation ◽  
Thermally Induced ◽  
Molecular Weights ◽  
Spinning Process ◽  
The Relationship

Polyvinylidene fluoride (PVDF) is an important material in the preparation of ultrafiltration membranes via the thermally induced phase separation (TIPS) method. In this paper, four PVDF hollow fiber membranes with different molecular weights were prepared via the TIPS method by using dibutyl phthalate and dioctyl phthalate as a mixed diluent. The relationship between the molecular weight of PVDF and its distribution, phase separation, crystallization behavior and spinning process has been systematically studied. The effects of three factors on the microstructure and properties of the PVDF membrane have been analyzed. The flow behaviors of the PVDF/diluent and PVDF melt were tested by a capillary rheometer and a melt flow rate instrument, respectively. A phase diagram of the membrane solution was determined by thermal polarizing microscope and differential scanning calorimetry. The crystallization behavior and angle of orientation of the membrane were tested by using a differential scanning calorimeter and a sound velocity orientation measurement instrument. The microstructures, such as the pore structure and crystalline grain structure, were observed by field emission scanning electron microscopy. Meanwhile, the properties of the membrane were examined from the view of water flux, porosity and tensile testing. The results showed that changes in the polymer molecular weights affected not only the dynamics but also the thermodynamics of phase separation in membrane formation. As the PVDF molecular weight increased, the phase separation region increased, but the membrane structure became denser. A wide molecular weight distribution easily produced large pores. Then, the water flux decreased first and then increased.

Effect of Pore-Forming Agents on Structure and Properties of PVDF/PVC Blend Membranes

2009 ◽  
Vol 79-82 ◽  
pp. 1627-1630 ◽  
Author(s):  
Hui Ling Shen ◽  
Lu Bai ◽  
Hua Liao ◽  
Chang Fa Xiao ◽  
Shi Ru Jia
Keyword(s):  
Pore Size ◽  
Polyvinylidene Fluoride ◽  
Phase Inversion ◽  
Capillary Flow ◽  
Removal Rate ◽  
Pure Water ◽  
Membrane Formation ◽  
Membrane Pore ◽  
Blend Membrane ◽  
Blend Membranes

By phase inversion process, the polyvinylidene fluoride (PVDF) with polyvinyl chloride (PVC) blend membrane was prepared. In which, as pore-forming agents, the polyethylene glycol (PEG), poly(vinylpyrrolidone) (PVP) and lithium chloride (LiCl) was separately added into PVDF/PVC casting solution. The effect of each pore-forming agent on the kinetics of membrane formation and properties of PVDF/PVC blend membrane were investigated respectively. Using the capillary flow porometry, the microstructure and morphology of PVDF/PVC blend membrane were quantitatively characterized. The results show that by respectively adding PEG, PVP or LiCl, it emphasizes the rate of solvent diffusion from PVDF/PVC solution during the phase inversion or membrane formation, and the porosity of membrane gets increasing. The pure water flux of PVDF/PVC blend membrane achieves enhancement obviously. At the same time, the rejection is decreased in a certain degree. Comparison with PEG or LiCl, PVP has more effect on the membrane pore-forming action. The microstructure analysis indicates that based on the same formulation, by selecting PEG or LiCl as pore-forming agent, formatted PVDF/PVC blend membranes achieve equivalent mean pore size. However, there is a little larger mean pore size distributed in the membrane by using PVP instead of PEG or LiCl. The application of purifying ε-polylysine (ε-PL) by using the PVDF/PVC blend membrane with PVP, the results reveal that the protein removal rate can be around 62.33% and the filterable and permeated ε-PL kept at 70.79% yield.

scholarly journals Development of Polyvinylidene Fluoride Membrane by Incorporating Bio-Based Ginger Extract as Additive

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2003
Author(s):  
Afrillia Fahrina ◽  
Nasrul Arahman ◽  
Sri Mulyati ◽  
Sri Aprilia ◽  
Normi Izati Mat Nawi ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Pure Water ◽  
Water Flux ◽  
Inhibition Zone ◽  
Diffusion Method ◽  
Ginger Extract ◽  
Dimethyl Acetamide ◽  
Antibiotic Property

Biofouling on the membrane surface leads to performance deficiencies in membrane filtration. In this study, the application of ginger extract as a bio-based additive to enhance membrane antibiofouling properties was investigated. The extract was dispersed in a dimethyl acetamide (DMAc) solvent together with polyvinylidene fluoride (PVDF) to enhance biofouling resistance of the resulting membrane due to its antibiotic property. The concentrations of the ginger extract in the dope solution were varied in the range of 0–0.1 wt %. The antibacterial property of the resulting membranes was assessed using the Kirby Bauer disc diffusion method. The results show an inhibition zone formed around the PVDF/ginger membrane against Escherichia coli and Staphylococcus aureus demonstrating the efficacy of the residual ginger extract in the membrane matrix to impose the antibiofouling property. The addition of the ginger extract also enhanced the hydrophilicity in the membrane surface by lowering the contact angle from 93° to 85°, which was in good agreement with the increase in the pure water flux of up to 62%.

Preparation and Characterization of BaTiO3/ PVDF Inorganic-Organic Composite Ultrafiltration Membranes

2011 ◽  
Vol 356-360 ◽  
pp. 2158-2161
Author(s):  
Ling Di Chen ◽  
Guo Xi Jin ◽  
Xiao Bo Wu ◽  
Wan Zhong Lang ◽  
Da Zhi Sun
Keyword(s):  
Cross Section ◽  
Polyvinylidene Fluoride ◽  
Water Flux ◽  
Ultrafiltration Membranes ◽  
Pvdf Membrane ◽  
Force Microscopy ◽  
Atomic Force ◽  
Spongy Layer ◽  
Blend Polymer

Abstract.BaTiO3-PVDF(polyvinylidene fluoride) composite ultrafiltration membranes were prepared by a phase separation method.The surface and cross-section of the membranes were investigated by atomic force microscopy and scanning electron microscope.The results showed that the morphology of PVDF membrane can be disturbed by BaTiO3.Albumin bovine serum retention and the water flux of the blend membrane increase.The phenomenon is discussed in terms of the modification of spongy layer and finger-like structure in the blend polymer.

Fabrication and Properties of the PVDF/PVDF-g-PMMA Blend Hydrophilic Membrane

2011 ◽  
Vol 418-420 ◽  
pp. 639-642
Author(s):  
Tao Yuan ◽  
Jian Qiang Meng ◽  
Guo Rong Cai ◽  
Yu Feng Zhang
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Polyvinylidene Fluoride ◽  
Membrane Surface ◽  
Pure Water ◽  
Water Flux ◽  
Water Contact ◽  
H Nmr ◽  
Membrane Surfaces ◽  
Static Water

An amphiphilic graft copolymer was obtained via atom transfer radical polymerization (ATRP) of methacrylate (MMA) initiated directly by polyvinylidene fluoride (PVDF). Hydrophilic PVDF membranes were prepared by immersion precipitation of PVDF-g-PMMA and PVDF blend solutions. The chemical structure and the molecular weight were characterized by 1H-NMR and GPC. The hydrophilicity of membrane surfaces were characterized by static water contact angle. Top surface and cross-section of membranes were observed by Field Emission Scanning Electron Microscope (FESEM). The results demonstrated the water contact angle of the membrane surface decreased from 89°to 67°, indicating enhanced hydrophilicity; the pure water flux water firstly decreased and then increased up to 1.7 times of the PVDF membrane. The retention of PEG (Mn=6000) could be maintained at 93%-95%.

scholarly journals Enhanced Performance of PVDF Composite Ultrafiltration Membrane via Degradation of Collagen-Modified Graphene Oxide

2021 ◽  
Vol 11 (23) ◽  
pp. 11513
Author(s):  
Yonggang Hou ◽  
Shenghua Lv ◽  
Haoyan Hu ◽  
Xinming Wu ◽  
Leipeng Liu
Keyword(s):  
Graphene Oxide ◽  
Polyvinylidene Fluoride ◽  
Membrane Surface ◽  
Water Flux ◽  
Ultrafiltration Membrane ◽  
Carboxyl Content ◽  
Modified Graphene Oxide ◽  
Leather Waste ◽  
Improved Performance ◽  
Modified Graphene

The collagen obtained from chrome leather waste can be used to modify graphene oxide (GO) to prepare polyvinylidene fluoride (PVDF) composite ultrafiltration membranes, a process that is conducive to the recovery of leather waste, comprehensive utilization of GO and improved performance of the membrane. In this paper, collagen-modified GO (CGO) was prepared by degradation of collagen from chrome leather waste and used to prepare a PVDF composite ultrafiltration membrane. The results show that the carboxyl content of CGO and dispersion were improved. The water flux and flux recovery rate of the modified ultrafiltration membrane were improved. The bovine serum albumin (BSA) intercepted on the membrane surface was easy to clean and the antifouling performance improved. The performance of the membrane decreased when the GO content exceeded 0.75 wt%, while CGO can reach 1.0 wt% without agglomeration due to its good dispersion.

Preparation and Characterization of PVDF-TiO2 Composite Membranes Blended with Different Mw of PVP for Oily Wastewater Treatment using Submerged Membrane System

2014 ◽  
Vol 69 (9) ◽  
Author(s):  
C. S. Ong ◽  
W. J. Lau ◽  
P. S. Goh ◽  
A. F. Ismail Ismail
Keyword(s):  
Polyvinylidene Fluoride ◽  
Membrane Surface ◽  
Pure Water ◽  
Water Flux ◽  
Composite Membranes ◽  
Membrane System ◽  
Morphological Properties ◽  
Oily Wastewater ◽  
Permeate Flux ◽  
Oily Wastewater Treatment

Polyvinylidene fluoride (PVDF) hollow fiber ultrafiltration (UF) membranes consisted of TiO2 and different molecular weight (Mw) of polyvinylpyrrolidone (PVP) (i.e. 10, 24, 40 and 360 kDa) were prepared to treat synthesized oily wastewater. The membrane performances were characterized in terms of pure water flux, permeate flux and oil rejection while the membrane morphological properties were studied using SEM and AFM. PVDF-TiO2 composite membrane prepared from PVP40k was found as the optimum membrane due to its high flux and high rejection during filtration process, recording      45 L/m2.h and 80% respectively, when tested using 250 ppm oily solution under submerged condition. The experimental results demonstrated that with increasing Mw of PVP, PVDF-TiO2 membrane had higher protein rejection, smaller porosity and smoother surface layer. With increasing oil concentration from 250 to 1000 ppm, the permeate flux of the PVDF-PVP40k was obviously decreased while the oil rejection was gradually increased due to the additional selective layer formed on the membrane surface.  Based on the findings, the PVDF-TiO2 membrane with PVP40k can be considered as a potential membrane for oily wastewater industry due to the high permeate flux and oil rejection. 

scholarly journals Construction of Loose Positively Charged NF Membrane by Layer-by-Layer Grafting of Polyphenol and Polyethyleneimine on the PES/Fe Substrate for Dye/Salt Separation

Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 699
Author(s):  
Shuai Liu ◽  
Xiaofeng Fang ◽  
Mengmeng Lou ◽  
Yihan Qi ◽  
Ruo Li ◽  
...  
Keyword(s):  
Alcian Blue ◽  
Membrane Surface ◽  
Pure Water ◽  
Water Flux ◽  
Textile Wastewater ◽  
Inorganic Salts ◽  
Bromophenol Blue ◽  
Layer By Layer ◽  
Operation Pressure ◽  
Term Performance

The effective separation of dyes and inorganic salts is highly desirable for recycling inorganic salts and water resource in printing and dyeing wastewater treatment. In this work, tannic acid (TA) and polyethyleneimine (PEI) were grafted on the PES/Fe ultrafiltration membrane via the coordination assembly and Michael addition strategy to fabricated a loose nanofiltration membrane (LNM). The effect of PEI concentration on membrane morphologies and properties was systematically investigated. The membrane surface becomes more hydrophilic and transforms into positive charge after the PEI grafting. The optimized PES/Fe-TA-PEI membrane possesses high pure water flux (124.6 L·m−2·h−1) and excellent dye rejections (98.5%, 99.8%, 98.4%, and 86.4% for Congo red, Eriochrome black T, Alcian blue 8GX, and Bromophenol blue, respectively) under 2 bar operation pressure. Meanwhile, the LNM showed a high Alcian blue 8GX rejection (>98.4%) and low NaCl rejection (<5.3%) for the dye/salt mixed solutions separation. Moreover, the PES/Fe-TA-PEI LNM exhibited good antifouling performance and long-term performance stability. These results reveal that such LNM shows great potential for effective fractionation of dyes and salts and recycling of textile wastewater.

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