Preparation and Characterization of Poly(vinylidene) Fluoride Membranes Reinforced by Modified Nano-SiO2 Particles

2014 ◽  
Vol 789 ◽  
pp. 201-204
Author(s):  
Ai Wen Qin ◽  
Xiang Li ◽  
Bo Mou Ma ◽  
Xin Zhen Zhao ◽  
Chun Yi Liu ◽  
...  

Poly (vinylidene fluoride) (PVDF) hybrid membranes reinforced by hydrophilic nanoSiO2 particles were fabricated from PVDF/N-dimethylacetamide (DMAc)/γ-butyrolactone (γ-BL) system via thermally induced phase separation (TIPS) process. Surface and cross-sectional morphology of membranes were characterized by scanning electron microscope (SEM). The properties such as permeability, mechanical performances and antifouling property were also determined. The results showed that the pore size of membrane surface became smaller, while cross-sectional morphology was changed from bicontinuous structure to cell structure, the pore size became larger and majorities of closed pores became open with the addition of hydrophilic nanoSiO2 particles in the system. Compared with pure membrane, pure water flux of hybrid membrane increased by 30.3%, i.e. from 290 to 378 L/(m2·h·0.1MPa), antifouling property increased from 63.1% to 80.2%. Meanwhile, tensile strength and elongation at break increased by 70.6% and124%, respectively.

2018 ◽  
Vol 18 (1) ◽  
pp. 1
Author(s):  
Romaya Sitha Silitonga ◽  
Nurul Widiastuti ◽  
Juhana Jaafar ◽  
Ahmad Fauzi Ismail ◽  
Muhammad Nidzhom Zainol Abidin ◽  
...  

Poly(vinylidene fluoride) (PVDF) has outstanding properties such as high thermal stability, resistance to acid solvents and good mechanical strength. Due to its properties, PVDF is widely used as a membrane matrix. However, PVDF membrane is hydrophobic properties, so as for specific applications, the surface of membrane needs to be modified to become hydrophilic. This research aims to modify PVDF membrane surface with chitosan and glutaraldehyde as a crosslinker agent. The FTIR spectra showed that the modified membrane has a peak at 1655 cm-1, indicating the imine group (–N=C)- that was formed due to the crosslink between amine group from chitosan and aldehyde group from glutaraldehyde. Results showed that the contact angle of the modified membrane decreases to 77.22° indicated that the membrane hydrophilic properties (< 90°) were enhanced. Prior to the modification, the contact angle of the PVDF membrane was 90.24°, which shows hydrophobic properties (> 90°). The results of porosity, Ɛ (%) for unmodified PVDF membrane was 55.39%, while the modified PVDF membrane has a porosity of 81.99%. Similarly, by modifying the PVDF membrane, pure water flux increased from 0.9867 L/m2h to 1.1253 L/m2h. The enhancement of porosity and pure water flux for the modified PVDF membrane was due to the improved surface hydrophilicity of PVDF membrane.


Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 323
Author(s):  
Nelisa Ncumisa Gaxela ◽  
Philiswa Nosizo Nomngongo ◽  
Richard Motlhaletsi Moutloali

The zwitterion poly-(maleic anhydride-alt-1-octadecene-3-(dimethylamino)-1-propylamine) (p(MAO-DMPA)) synthesized using a ring-opening reaction was used as a poly(vinylidene fluoride) (PVDF) membrane modifier/additive during phase inversion process. The zwitterion was characterized using proton nuclear magnetic resonance (1HNMR) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Atomic force microscopy (AFM), field emission scanning electron microscope (SEM), FTIR, and contact angle measurements were taken for the membranes. The effect of the zwitterionization content on membrane performance indicators such as pure water flux, membrane fouling, and dye rejection was investigated. The morphology of the membranes showed that the increase in the zwitterion amount led to a general decrease in pore size with a concomitant increase in the number of membrane surface pores. The surface roughness was not particularly affected by the amount of the additive; however, the internal structure was greatly influenced, leading to varying rejection mechanisms for the larger dye molecule. On the other hand, the wettability of the membranes initially decreased with increasing content to a certain point and then increased as the membrane homogeneity changed at higher zwitterion percentages. Flux and fouling properties were enhanced through the addition of zwitterion compared to the pristine PVDF membrane. The high (>90%) rejection of anionic dye, Congo red, indicated that these membranes behaved as ultrafiltration (UF). In comparison, the cationic dye, rhodamine 6G, was only rejected to <70%, with rejection being predominantly electrostatic-based. This work shows that zwitterion addition imparted good membrane performance to PVDF membranes up to an optimum content whereby membrane homogeneity was compromised, leading to poor performance at its higher loading.


2014 ◽  
Vol 981 ◽  
pp. 891-894 ◽  
Author(s):  
Yun Wei Guo ◽  
Wei Wei Cui ◽  
Wen Hua Xu ◽  
Yang Jiang ◽  
Hui Hui Liu ◽  
...  

This work describes the preparation and the properties of poly(vinylidene fluoride) (PVDF) porous membranes. The porous membrane was prepared using phase-inversion method by adding hydrophilic polyvinylpyrrolidone (PVP) as hole-agent. The contrastive analysis of membrane characterizations between the membrane no PVP added and the membrane added PVP were carried out by optical microscopy analysis, scanning electron microscopy, porosity, pure water flux and water contact angle. The results showed that adding PVP can induce the building of pore structure, increase the surface roughness and hydrophilicity of PVDF membrane, and then enhance its pure water flux.


Membranes ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 36 ◽  
Author(s):  
Francesca Russo ◽  
Claudia Ursino ◽  
Elisa Avruscio ◽  
Giovanni Desiderio ◽  
Andrea Perrone ◽  
...  

Electrospinning is an emerging technique for the preparation of electrospun fiber membranes (ENMs), and a very promising one on the basis of the high-yield and the scalability of the process according to a process intensification strategy. Most of the research reported in the literature has been focused on the preparation of poly (vinylidene fluoride) (PVDF) ENMs by using N,N- dimethylformamide (DMF) as a solvent, which is considered a mutagenic and cancerogenic substance. Hence, the possibility of using alternative solvents represents an interesting approach to investigate. In this work, we explored the use of dimethyl sulfoxide (DMSO) as a low toxicity solvent in a mixture with acetone for the preparation of PVDF-ENMs. As a first step, a solubility study of the polymer, PVDF 6012 Solef®, in several DMSO/acetone mixtures was carried out, and then, different operating conditions (e.g., applied voltage and needle to collector plate distance) for the successful electrospinning of the ENMs were evaluated. The study provided evidence of the crucial role of solution conductivity in the electrospinning phase and the thermal post-treatment. The prepared ENMs were characterized by evaluating the morphology (by SEM), pore-size, porosity, surface properties, and performance in terms of water permeability. The obtained results showed the possibility of producing ENMs in a more sustainable way, with a pore size in the range of 0.2–0.8 µm, high porosity (above 80%), and water flux in the range of 11.000–38.000 L/m2·h·bar.


2012 ◽  
Vol 465 ◽  
pp. 229-233 ◽  
Author(s):  
Xiao Mian Liu ◽  
Zong Hua Wang ◽  
Bing Yu ◽  
Hai Lin Cong ◽  
Xiu Ling Gao ◽  
...  

Polymethylmethacrylate (PMMA) modified poly(vinylidene fluoride) (PVDF) hollow fiber ultrafiltration membranes were prepared by wet spinning method using polyvinylpyrrolidone (PVP) as pore-foaming agent and mixture of dimethyl formamide (DMF)/methyl ethyl ketone (MEK) as solvent. The effects of PVDF, PMMA, PVP, and solvent ratios in the spinning solution on the permeation properties of the formed membranes were studied. The results showed that the performance of the membrane is the best with a pure water flux of 117 L/m2•h and rejection rate of 82% to bovine serum albumin (BSA), when the concentrations of PVDF, PMMA, PVP, DMF and MEK are 17, 3, 3, 60 and 17 wt%, respectively.


2015 ◽  
Vol 713-715 ◽  
pp. 2723-2726
Author(s):  
Yue Rong Shi ◽  
Gui Fang Zhang ◽  
Xing Tian Liu ◽  
Xue Tao Tian ◽  
Yi Ping Zhao ◽  
...  

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.


Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 724 ◽  
Author(s):  
Ouassila Benhabiles ◽  
Francesco Galiano ◽  
Tiziana Marino ◽  
Hacene Mahmoudi ◽  
Hakim Lounici ◽  
...  

The approach of the present work is based on the use of poly (methylmethacrylate) (PMMA) polymer, which is compatible with PVDF and TiO2 nanoparticles in casting solutions, for the preparation of nano-composites membranes using a safer and more compatible solvent. TiO2 embedded poly (vinylidene fluoride) (PVDF)/PMMA photocatalytic membranes were prepared by phase inversion method. A non-solvent induced phase separation (NIPS) coupled with vapor induced phase separation (VIPS) was used to fabricate flat-sheet membranes using a dope solution consisting of PMMA, PVDF, TiO2, and triethyl phosphate (TEP) as an alternative non-toxic solvent. Membrane morphology was examined by scanning electron microscopy (SEM). Backscatter electron detector (BSD) mapping was used to monitor the inter-dispersion of TiO2 in the membrane surface and matrix. The effects of polymer concentration, evaporation time, additives and catalyst amount on the membrane morphology and properties were investigated. Tests on photocatalytic degradation of methylene blue (MB) were also carried out using the membranes entrapped with different concentrations of TiO2. The results of this study showed that nearly 99% MB removal can be easily achieved by photocatalysis using TiO2 immobilized on the membrane matrix. Moreover, it was observed that the quantity of TiO2 plays a significant role in the dye removal.


2015 ◽  
Vol 6 (2) ◽  
pp. 280-289
Author(s):  
Baoli Shi ◽  
Zheng Li ◽  
Xing Su

A UV photo-grafting method was utilised to enhance the hydrophilicity and anti-fouling property of self-made poly(vinylidene fluoride) (PVDF) ultrafiltration membranes. N,N′-methylene-bisacrylamide (MBAA) was used as monomer and Ce(IV) was used as initiator to obtain balance between grafting treatment consumption and enhanced performance. MBAA could be grafted onto the surface of pure PVDF membranes through a water-phase grafting method under UV photoradiation. When the MBAA concentration was 0.07 mol/L, the Ce(IV) concentration was 0.04 mol/L, and the irradiation duration was 3 min, the membrane surface was grafted with a sufficient amount of monomer under a UV photoradiation intensity of 5.0 mW/cm2. The water contact angle on the surface of the modified membrane decreased by approximately 16°, and flux recovery increased by approximately 40% compared with the pure PVDF membrane when treating river water. For bovine serum albumin rejection and porosity measurements no significant changes were observed between pure PVDF and graft-treated membranes. The enhanced performance of the modified membrane in this work was moderate, but the UV irradiation duration (3 min) was short. The integrative effects of UV modification in this work were satisfactory when both irradiation duration and enhanced performance were considered.


2012 ◽  
Vol 66 (11) ◽  
pp. 2343-2348 ◽  
Author(s):  
Xingtao Zuo ◽  
Wenxin Shi ◽  
Shuili Yu ◽  
Jiajie He

A new type of poly(vinylidene fluoride)(PVDF)–SiO2 hybrid anion-exchange membrane was prepared by blending method. The anion-exchange groups were introduced by the reaction of epoxy groups with trimethylamine (TMA). Contact angle between water and the membrane surface was measured to characterize the hydrophilicity change of the membrane surface. The effects of nano-sized SiO2 particles in the membrane-forming materials on the membrane mechanical properties and conductivity were also investigated. The experimental results indicated that PVDF–SiO2 anion-exchange membranes exhibited better water content, ion-exchange capacity, conductivity and mechanic properties, and so may find potential applications in alkaline membrane fuel cells and water treatment processes.


Sign in / Sign up

Export Citation Format

Share Document