Polyvinylidene Fluoride Nanocomposite Membrane Research Articles

Nanocomposite PVDF Membrane for Battery Separator Prepared via Hot Pressing

Polyvinylidene fluoride (PVDF) is one of the materials most commonly used in membrane separators. The structures of pristine PVDF and PVDF nanocomposite films were processed via hot pressing at 140 °C, 170 °C, and 185 °C at a pressure of 2 tons for 15 min. According to a surface investigation using scanning electron microscopy (SEM), the spherulitic character of the PVDF nanocomposite films was preserved up to a pressing temperatures of 140 °C. The cross-sectional SEM images confirmed that higher pressing temperatures (170 °C) caused the structures to be compacted into monolithic films, and a pressing temperature of 185 °C caused the melting of the PVDF matrix and its recrystallization into thin films (21–29 μm). An average crystallinity value of 51.5% was calculated using differential scanning calorimetry (DSC), and this decreased as the pressing temperature increased. Fourier transform infrared (FTIR) measurements confirmed the presence of a dominant γ phases in the PVDF nanocomposite films, whose nanofillers consisted of vermiculite particles (ZnO_V and ZnO_V_CH) and mixed α + γ phases. The percentage of the electroactive γ phase (approximately 79%) was calculated via a FTIR analysis, and the ratio between the β phase and the α phase was determined from the Raman spectra. A hydrophilic surface with contact angles ranging from 61 to 84° was demonstrated for all the PVDF nanocomposite membranes. The superoleophilic surface was measured using poly(dimethylsiloxane) with contact angles ranging from 4 to 13°, and these angles reached lower values when in contact with sulfur particles.

Sonocatalytic degradation of ciprofloxacin and organic pollutant by 1T/2H phase MoS2 in Polyvinylidene fluoride nanocomposite membrane

The development of recyclable catalysts with effective properties and stable reusability is great importance for the removal of different types of pollutants in wastewater. Herein, we have synthesized Polyvinylidene fluoride (PVDF) polymer and mixed-phase 1T/2H MoS2 for immobilizing the sonocatalyst material. Techniques such as FESEM, XRD, FTIR, XPS, and UV–vis spectra have been used for analyzing the structural, and morphological properties. The formation of a 1T/2H mixed phase in MoS2 has been revealed by XRD and XPS analysis. Consequently, the sonocatalytic performance of the nanocomposite membrane was investigated through ciprofloxacin (CIP) and organic pollutants (Rhodamine B (RhB)). As a result, MoS2/PVDF (PM4) nanocomposite membrane exhibited a superior sonocatalytic activity with 94.37% and 84.37% of RhB and CIP degradation efficiency with pseudo-first-order kinetic constant (k) of 0.0187 min−1, and 0.0044 min−1. The sonocatalytic property of the nanocomposite membrane is related to 1T/2H mixed-phase and PVDF. Additionally, the metallic based 1T phase MoS2 helps to promote electrons and holes and reduce the recombination rate. Moreover, it promotes the generation of more hydroxy radicals (.OH), and superoxide radicals (∙O2−) play a significant role in sonocatalytic degradation of RhB pollutants. Thus, the improved sonocatalytic degradation of 1T/2H MoS2/PVDF composite membrane exhibited its application in real-time wastewater treatment.

Modification of PVDF membranes by incorporation Fe3O4@Xanthan gum to improve anti-fouling, anti-bacterial, and separation performance

This study describes the synthesis and characterization of Fe3O4@Xanthan gum (XG) nanocomposite with increased hydrophilicity and anti-bacterial properties, and its application in the fabrication of nanocomposite-based mixed matrix polyvinylidene fluoride (PVDF) membrane using the phase inversion method. The Fe3O4@XG was synthesized by the in-situ co-precipitation technique. The characteristics of the membranes were investigated in terms of morphology, dye and BSA removal performance, anti-fouling behavior, and anti-bacterial properties. The incorporation of very small amounts of Fe3O4@XG NPs, i.e. 0.1 and 0.2 wt%, improved 5% and 17% water flux of the PVDF nanocomposite membranes due to the increased membrane hydrophilicity. Most particular, 0.5 wt% Fe3O4@XG/PVDF membrane was revealed a maximum water flux of 167.2 L·m−2·h−1 at 3 bar, which was 52% greater performance than the pure PVDF membrane. Reactive Black 5 and Reactive Red 120 dye rejections were enhanced from 77.6% to 84.8% and 66.6–73.8% respectively in 0.2 wt% Fe3O4@XG/PVDF membrane compared to the pure PVDF membrane. The best anti-fouling performance was also exhibited by 0.2 wt% Fe3O4@XG/PVDF membrane with an increased FRR value (66.5%) compared with the pure one. In addition, the results of the anti-bacterial test with E. coli showed that the anti-bacterial capabilities of the Fe3O4@XG/PVDF membranes were remarkable and have resisted contamination.

Sonocatalytic Degradation of Ciprofloxacin and Organic Pollutant by 1t/2h Phase Mos2 in Polyvinylidene Fluoride Nanocomposite Membrane

Sonocatalytic Degradation of Ciprofloxacin and Organic Pollutant by 1t/2h Phase Mos2 in Polyvinylidene Fluoride Nanocomposite Membrane

Fabrication and Characterization of Sulfonated Graphene Oxide (SGO) Doped PVDF Nanocomposite Membranes with Improved Anti-Biofouling Performance.

Emergence of membrane technology for effective performance is qualified due to its low energy consumption, no use of chemicals, high removal capacity and easy accessibility of membrane material. The hydrophobic nature of polymeric membranes limits their applications due to biofouling (assemblage of microorganisms on surface of membrane). Polymeric nanocomposite membranes emerge to alleviate this issue. The current research work was concerned with the fabrication of sulfonated graphene oxide doped polyvinylidene fluoride (PVDF) membrane and investigation of its anti-biofouling and anti-bacterial behavior. The membrane was fabricated through phase inversion method, and its structure and morphology were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-rays diffraction (XRD) and thermo gravimetric analysis (TGA) techniques. Performance of the membrane was evaluated via pure water flux; anti-biofouling behavior was determined through Bovine Serum albumin (BSA) rejection. Our results revealed that the highest water flux was shown by M7 membrane about 308.7 Lm−2h−1/bar having (0.5%) concentration of SGO with improved BSA rejection. Furthermore, these fabricated membranes showed high antibacterial activity, more hydrophilicity and mechanical strength as compared to pristine PVDF membranes. It was concluded that SGO addition within PVDF polymer matrix enhanced the properties and performance of membranes. Therefore, SGO was found to be a promising material for the fabrication of nanocomposite membranes.

Cationic dyes adsorption study on graphene- Polyvinylidene fluoride ‎nanocomposite membranes

Polyvinylidene fluoride (PVDF) is one of the well-known polymers in different types of ‎membranes for water treatment applications, because of its unique chemical, mechanical and ‎thermal properties. Because of the presence of fluorine groups in polymer chain, the PVDF has ‎a negative electrostatic surface charge that makes the PVDF a suitable adsorbing material for ‎cationic dyes such as Rhodamine B (RB) and Methylene Blue (MB). The presence of two-‎dimensional graphene oxide sheets with negative electrostatic surface charge in the PVDF ‎matrix, can improve the adsorption of the dyes on PVDF/graphene oxide (PGO) composite ‎membranes due to increasing of negative electrostatic charge. In this study, we aimed to ‎explore synthesis and characterization of the PGO composite membranes by Scanning Electron ‎Microscopy (SEM), Atomic Force Microscopy (AFM), Raman spectroscopy, X-Ray diffraction ‎‎(XRD), to confirm the effective presence of the GO sheets in PVDF matrix. In continue, the ‎mechanisms of physical adsorption of the dyes on PGO membranes have been investigated‎‎.‎

Effect of silica nanotubes on characteristic and performance of PVDF nanocomposite membrane for nitrate removal application

In this work, impact of synthesized silica nanotubes (SNTs) on morphology and performance of polyvinylidene fluoride (PVDF) nanocomposite membrane was studied. For this purpose, SNTs were synthesized using hydrothermal method, characterized by different techniques, and finally used as filler in nanocomposite membrane preparation. The PVDF/SNTs nanocomposite membranes were fabricated via phase inversion method at different dosage of SNTs (1–6 wt.%). As-prepared membranes and SNTs were characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and contact angle measurement. The results confirmed by incrementing SNTs dosage, hydrophilicity of PVDF membrane was increased. The effect of SNTs on the membrane performance was studied through nitrate removal at operating pressure of 7 bar. The results showed that the optimal performance parameters (nitrate rejection and pure water permeability (PWP) were obtained at SNTs dosage of 4%. The effect of feed concentration (50, 100, and 150 mg/L) on nitrate separation performance was also investigated and it was found that the maximum rejection of 86% and PWP of 11.58 (L/m2.h.bar) were achieved for optimum PVDF/SNTs membrane at 150 mg/L. Finally, antifouling properties of optimum PVDF/SNTs membrane were investigated.

Effects of heat treatment of TiO2 nanofibers on the morphological structure of PVDF nanocomposite membrane under UV irradiation

Nowadays, photocatalytic oxidation has been pledged as a valuable process for air and water purification due to its capability in degrading organic pollutants. In this study, polyvinylidene fluoride (PVDF) nanocomposite membrane consisted of electrospun titanium dioxide nanofibers (PVDF/TNF) was prepared by hot pressing TNF onto PVDF flat sheet membrane. Titanium dioxide nanofibers (TNF) were successfully fabricated through electrospinning technique, in which electrospun from a precursor solution consisted of polyvinylpyrrolidone (PVP)/titanium tetraisopropoxide (TTIP), ethanol and acetic acid. They were then heat-treated under different calcination temperatures ranging from 400 to 600°C. The morphological properties of TNF were characterized via scanning of electron microscope (SEM) and X-ray diffractometer (XRD). From the results collected, it is shown that the heat-treated TNF were consisted of anatase and rutile phases, whereas the un-treated TNF only possessed amorphous phase as analysed by XRD analysis. As a matter of fact, TNF-500 displayed satisfactory morphological structure, along with fiber diameter and crystalline structure compared to other TNF, thus TNF-500 was chosen for further testing. In addition, selected TNF have successfully deposited onto PVDF membrane as there is no visible lift-off. By introducing TNF into PVDF membrane matrix, said course of action resulted in a tremendously enhanced BPA photodegradation up to 85.88%. Even though the calcination process implemented on TNF has been reduced to about 4% in photocatalytic activity, further optimisation study on the loading of TNF-500 in PVDF membrane matrix could highlight favourable features of calcined TNF-500 for BPA degradation reaction.

Omega-3 PUFA concentration by a novel PVDF nano-composite membrane filled with nano-porous silica particles.

The concentration of omega-3 polyunsaturated fatty acids (PUFA) is important in the oil industries. While the current methods demand high energy consumptions in concentrating the omega-3, membrane separation technology offers noticeable advantages in producing pure omega-3 PUFA. Moreover, concentrating omega-3 via membrane separation produces products in the triacylglycerol form which possess better oxidative stability. In this work, the detailed mechanisms of fouling which limits the performance of membrane separation were investigated. Incorporating silica particles to polymeric membrane resulted in the formation of mixed matrix membrane with improved anti-fouling behaviour compared to the neat polymeric membrane. Hence, the industrial potential of membrane processing to concentrate omega-3 fatty acids is enhanced.

Membranes of Polyvinylidene Fluoride and PVDF Nanocomposites with Carbon Nanotubes via Immersion Precipitation

Microporous polyvinylidene fluoride (PVDF) and PVDF nanocomposite membranes were prepared via an isothermal immersion precipitation method using two different antisolvents (ethanol and water). The structure and morphology of the resulting membranes were investigated by wide angle X‐ray diffraction (WAXD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The effects of the type of the antisolvent and the presence of multiwalled carbon nanotubes (MWNTs) on membrane morphology and the crystal structure developed within the membranes were studied. The crystallization of the PVDF upon immersion precipitation occurred predominantly in the α‐phase when water is used as the antisolvent or in the absence of the carbon nanotubes. On the other hand, β‐phase crystallization of the PVDF was promoted upon the use of ethanol as the antisolvent in conjunction with the incorporation of the MWNTs. The morphology and the total crystallinity of the PVDF membranes were also affected by the incorporation of the MWNTs and the antisolvent used, suggesting that the microstructure and the ultimate properties of the PVDF membranes can be engineered upon the judicious selection of crystallization conditions and the use of carbon nanotubes.