scholarly journals Ti3C2/PVDF membrane for efficient seawater desalination based on interfacial solar heating

2020 ◽  
Author(s):  
Huan Peng ◽  
Kehang Zhu ◽  
Chenxing Li ◽  
Yangyi Xiao ◽  
Miaomiao Ye
Keyword(s):  
Water Quality ◽  
Polyvinylidene Fluoride ◽  
Evaporation Rate ◽  
Pure Water ◽  
Solar Heating ◽  
Water Evaporation ◽  
Seawater Desalination ◽  
Limit Values ◽  
Pvdf Membrane ◽  
Us Epa

Abstract Photothermal material of Ti3C2 has been synthesized by etching Ti3AlC2 with hydrofluoric acid. The as-prepared Ti3C2 was deposited on a polyvinylidene fluoride (PVDF) membrane via vacuum filtration to form Ti3C2/PVDF membrane, which was used for seawater desalination in the next step based on interfacial solar heating. The water evaporation rate of the Ti3C2/PVDF membrane could be enhanced to 0.98 kg/m2·h under 2 sun irradiance, which was 2.8 times and 5.4 times higher than that of pure water (0.35 kg/m2·h) and PVDF (0.18 kg/m2·h) respectively. The temperature difference between the two air–water interfaces with and without the Ti3C2/PVDF membrane was as high as 11.8 °C, confirming the interfacial heating behavior. The water evaporation rate under 2 sun irradiance almost kept in the range of 0.96–0.86 kg/m2·h over 30 days under continuous operation, indicating the high stability of the Ti3C2/PVDF membrane. Finally, it was demonstrated that the typical water-quality indexes of the condensed fresh water was below the limit values of the Standards for Drinking Water Quality in China, WHO, and US EPA.

Preparation and Characterization of Hydrophilic PVDF Membrane via Graft Modification by Maleic Anhydride

2011 ◽  
Vol 295-297 ◽  
pp. 286-291
Author(s):  
Li Guo Wang ◽  
Xiao Guang Zhang ◽  
Shu Fang Hou ◽  
Xiu Ju Wang ◽  
Ai Min Wang ◽  
...  
Keyword(s):  
Maleic Anhydride ◽  
Polyvinylidene Fluoride ◽  
Pure Water ◽  
Water Flux ◽  
Pvdf Membrane ◽  
Technical Parameters ◽  
Pure Water Flux ◽  
Flat Membranes ◽  
Better Than

Hydrophilic polyvinylidene fluoride (PVDF) flat ultrafiltration membranes were prepared by wet-spinning method. The effects of technical parameters of maleic anhydride grafted onto PVDF on the performance of hydrophilic PVDF membranes were investigated, the preparation technical parameters were determined, and the hydrophilic PVDF flat membranes were prepared. Then, hydrophilic PVDF membranes were characterized in terms of pure water flux, contact angle, infrared spectroscopic analysis and scanning electron microscope(SEM). The results showed that maleic anhydride had been grafted onto PVDF, and the hydrophilic performance of the modified membrane was better than the traditional one.

scholarly journals Synthesis, characterization and filtration performance of the polyvinylidene fluoride membrane modified by poly(methyl ethacrylate-co-2-acrylamido-2-methylpropane sulfonic acid)

2018 ◽  
Vol 19 (4) ◽  
pp. 1279-1285
Author(s):  
Q. Y. Zhang ◽  
Q. An ◽  
Y. G. Guo ◽  
J. Zhang ◽  
K. Y. Zhao
Keyword(s):  
Sulfonic Acid ◽  
Polyvinylidene Fluoride ◽  
Phase Inversion ◽  
Pure Water ◽  
Water Flux ◽  
Contact Angles ◽  
Fouling Resistance ◽  
Inversion Process ◽  
Pvdf Membrane ◽  
Pure Water Flux

Abstract To enhance the anti-fouling and separating properties of polyvinylidene fluoride (PVDF) membranes, an amphiphilic copolymer of methyl methacrylate and 2-acrylamido-2-methylpropane sulfonic acid, poly(MMA-co-AMPS), was designed and synthesized. Through a phase-inversion process, the poly(MMA-co-AMPS) were fully dispersed in the PVDF membrane. The properties of membrane including the surface and cross-section morphology, surface wettability and fouling resistance under different pH solutions were investigated. Compared to the unmodified PVDF membranes, the contact angles of modified PVDF membranes decreased from 80.6° to 71.6°, and the pure water flux increased from 54 to 71 L·m−2·h−1. In addition, the hybrid PVDF membrane containing 0.5 wt% copolymers demonstrated an larger permeability, better fouling resistance and higher recovery ratio via pure water backlashing, when it was compared with the other blend membranes, and the virgin one in the cyclic test of anti-fouling. The modified membranes with the copolymers possessed an outstanding performance and may be used for further water treatment applications.

scholarly journals Hierarchical Porous Aero-Cryogels for Wind Energy Enhanced Solar Vapor Generation

2021 ◽  
Author(s):  
Shuai Li ◽  
Xiaochun Yang ◽  
Yingying He ◽  
Yanan Wang ◽  
Daogui Liao ◽  
...  
Keyword(s):  
Wind Energy ◽  
Evaporation Rate ◽  
High Efficiency ◽  
Pure Water ◽  
Water Evaporation ◽  
Vapor Generation ◽  
Hierarchical Porous ◽  
Evaporation Enthalpy ◽  
Absorbing Layer ◽  
Transport Channels

Abstract An integrated aero-cryogel (A-CG) monolith with hierarchical porous structure was developed by inter-crosslinking of cellulose nanofiber (CNF)/polylactic acid (PLA) nanocomposite aerogel and carboxymethyl cellulose (CMC) cryogel. The photothermal nanoparticles-enriched CMC cryogel phase served as a sunlight absorbing layer, exhibiting a broadband sunlight absorption of 98%. Due to the large amount of weakly bounded water molecules, the swelled CMC cryogel possessed a lower evaporation enthalpy than that of pure water, which facilitates water evaporation, while the nanocomposite aerogel phase acted as an excellent thermal insulator and afforded highly efficient water transport channels. Thus, the developed A-CG monolith supported by insulated polystyrene foam to protrude above the water surface, could reach an evaporation rate of 2.16 kg m-2 h-1 under an irradiation of 1 Sun (100 mw/cm2) with an efficiency of 93.6%. More remarkably, when the wind energy was imparted, an evaporation rate of 5.67 kg m-2 h-1 was achieved at a wind speed of 3 m s-1. The high-efficiency purification outcomes of various raw water demonstrate the great potentials of A-CG material in solar vapor generation.

scholarly journals A Membrane Modified with Nitrogen-Doped TiO2/Graphene Oxide for Improved Photocatalytic Performance

2019 ◽  
Vol 9 (5) ◽  
pp. 855
Author(s):  
Tingting Li ◽  
Yong Gao ◽  
Junwo Zhou ◽  
Manying Zhang ◽  
Xiaofei Fu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Polyvinylidene Fluoride ◽  
Membrane Surface ◽  
Pure Water ◽  
Impregnation Method ◽  
Photocatalytic Efficiency ◽  
Pvdf Membrane ◽  
Microfiltration Membrane ◽  
Doped Tio2 ◽  
Nitrogen Doped

An improved photocatalytic microfiltration membrane was successfully prepared by the impregnation method with nitrogen-doped TiO2/graphene oxide (GO) (NTG). By utilizing the unique role of N and GO, the photocatalytic activity of the membrane in UV and sunlight was improved. Compared with the Polyvinylidene Fluoride (PVDF) microfiltration membrane which was modified by TiO2, N-TiO2 (NT) and TiO2-GO (TG), the NTG/PVDF membrane exhibited high photocatalytic efficiency and significantly improved photodegradation power to the methylene blue (MB) solution under ultraviolet light and sunlight, with the photocatalytic efficiency reaching 86.5% and 80.6%, respectively. Scanning electron microscopy (SEM), X-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FT-IR) were used to analyze the morphology, crystal structure and chemical bonds of the membrane surface. The hydrophilicity of the modified PVDF microfiltration membrane was significantly improved, the flux of the pure water membrane reached 1672 Lm−2h−1, the flux of the MB solution was also significantly improved due to photodegradation. Therefore, the nitrogen-doped titanium dioxide graphene oxide PVDF microfiltration membrane (NTG/PVDF membrane) has great development prospects in sustainable water treatment.

scholarly journals Macroporous 3D MXene architecture for solar-driven interfacial water evaporation

2019 ◽  
Vol 09 (06) ◽  
pp. 1950047 ◽  
Author(s):  
Maomao Ju ◽  
Yawei Yang ◽  
Jianqiu Zhao ◽  
Xingtian Yin ◽  
Yutao Wu ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Evaporation Rate ◽  
Solar Heating ◽  
Water Evaporation ◽  
Interfacial Water ◽  
Wastewater Purification ◽  
Solar Absorption ◽  
Promising Strategy ◽  
3D Architecture ◽  
High Reflection

Interfacial water evaporation through solar heating with photothermal materials is a promising strategy for seawater desalination and wastewater purification. Tightly packed 2D membranes with high reflection losses and limited vapor escape channels result in a low evaporation rate. In this work, 3D MXene architecture was fabricated by dropping the delaminated Ti3C2 ([Formula: see text]-Ti3C2) nanosheets onto the carbonized melamine foam (CMF) framework. Owing to the macroporous 3D architecture, more effective broadband solar absorption and vapor escaping were achieved. As a result, the 3D CMF@[Formula: see text]-Ti3C2-based evaporator delivers a water evaporation rate of 1.60[Formula: see text]kg/m2[Formula: see text][Formula: see text][Formula: see text]h with a solar-to-vapor conversion efficiency of up to 84.6%.

Excellent hydrophilicity of polyurethane modified polyvinylidene fluoride

2021 ◽  
pp. 1-8
Author(s):  
Jiale Qu ◽  
Shen Gao ◽  
Zhenghao Hou
Keyword(s):  
Polyvinylidene Fluoride ◽  
Pure Water ◽  
Water Flux ◽  
Membrane Properties ◽  
Pvdf Membrane ◽  
Sem Image ◽  
Low Surface Energy ◽  
Blending Method ◽  
Pure Water Flux ◽  
Pure Pvdf

Polyvinylidene fluoride (PVDF) is a promising membrane material in ultrafiltration (UF) applications; its extensive application however is limited due to the disadvantage in hydrophilicity and low surface energy. Herein, a sort of TPU-modified PVDF membrane is prepared by blending method and its hydrophilicity is compared with a series of pure/modified PVDF membranes. The contact angle and pure water flux (PWF) results demonstrate that the hydrophilicity of the TPU-modified PVDF membrane is enhanced, and the performance is not inferior to that of traditional pore-modified PVDF membranes. SEM image shows that the TPU-modified PVDF membrane maintains morphology of the pure PVDF membrane, indicating that TPU molecules have excellent compatibility with PVDF molecules and can maintain the mechanical property of PVDF membrane to a certain extent. Finally, we explore the effects of TPU molecules and PVDF molecules on water molecules, respectively, from a microscopic perspective involving first principles. This investigation not only establishes that PVDF membrane has been prepared with enhanced hydrophilicity, but also provides a novel avenue for the modification of membrane properties.

scholarly journals Magnetic Field Effects on Aqueous Anionic and Cationic Surfactant Solutions Part I: Water Evaporation

2019 ◽  
pp. 7-13
Author(s):  
Emil Chibowski ◽  
Aleksandra Szcześ
Keyword(s):  
Magnetic Field ◽  
Evaporation Rate ◽  
Pure Water ◽  
Sodium Dodecyl ◽  
Surfactant Solution ◽  
Water Evaporation ◽  
Ammonium Bromide ◽  
Magnetic Field Effects ◽  
Water Amount ◽  
Common Laboratory

Static magnetic field (0.5 T) effects on water evaporation rate from anionic Sodium Dodecyl Sulfate (SDS) and cationic Dodecyl Trimethyl ammonium Bromide (DoTAB) 1 mM solutions were studied at room temperature and humidity for up to several hours. Keeping in mind possible practical application of the effects the experiments were intentionally carried out in a common laboratory environment and not in any sophisticated conditions. The evaporation of water from Magnetic Field (MF) treated and untreated samples were carried out simultaneously in the same environment. Although the quantitative differences in the evaporated amounts of water between MF treated and untreated samples changed from run to run, the qualitative MF effects were always reproducible. Therefore, it is believed that the observed changes are significant. It was found that the MF affects evaporation rate of water from solutions of both surfactants causing increase in the evaporated water amount in comparison to that of MF untreated sample. Prior to MF experiments first the water evaporation rate from the untreated surfactants solutions was studied. From the MF-untreated anionic surfactant solution water evaporated slower than from pure water, while from the cationic one water evaporated faster than from pure water. This difference was explained taking into account the properties of the polar (ionic) head of the surfactants, i.e. their size, ability to hydrogen bonding formation with water molecules, and the reduction of water surface tension. The MF treatment caused an increase in the evaporated water amount from both surfactants. However, a greater effect was observed for cationic DoTAB. Because the hydrocarbon tail in both surfactants is the same (C12) the observed differences were assigned to the differences in their ionic heads. Gibbs adsorption equation and Lorentz force in the gradient MF were applied to explain the differences.

Preparation and Characterization of Hydrophilic PVDF Membrane via Graft Modification by Acrylic Acid

2011 ◽  
Vol 306-307 ◽  
pp. 1563-1568 ◽  
Author(s):  
Li Guo Wang ◽  
Xiao Guang Zhang ◽  
Shu Fang Hou ◽  
Xiu Ju Wang ◽  
Ai Min Wang ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Polyvinylidene Fluoride ◽  
Pure Water ◽  
Water Flux ◽  
Pvdf Membrane ◽  
Technical Parameters ◽  
Pure Water Flux ◽  
Flat Membranes ◽  
Better Than

Hydrophilic polyvinylidene fluoride (PVDF) flat ultrafiltration membranes were prepared by wet-spinning method. The effects of technical parameters of acrylic acid grafted onto PVDF on the performance of hydrophilic PVDF membranes were investigated, the technical parameters of preparation of hydrophilic PVDF membranes were determined, and hydrophilic PVDF flat membranes were prepared. Then, hydrophilic PVDF membranes were characterized in terms of pure water flux, contact angle, infrared spectroscopic analysis and scanning electron microscope (SEM). The results showed that acrylic acid had been grafted onto PVDF, and the hydrophilic performance of the modified membrane was better than the traditional one.

Rational design of reduced graphene oxide film for solar thermal desalination

2019 ◽  
Vol 19 (6) ◽  
pp. 1704-1710
Author(s):  
Yuan Meng ◽  
Haibo Li
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Rational Design ◽  
Evaporation Rate ◽  
Pure Water ◽  
Cost Effective ◽  
Solar Thermal ◽  
Water Evaporation ◽  
Reduced Graphene ◽  
Thermal Desalination

Abstract Solar water evaporation assisted by photothermal membranes is considered to be one of the sustainable and cost-effective strategies for pure water generation and wastewater treatment. In this work, a self-assembled reduced graphene oxide (rGO) film has been prepared and proposed for direct solar thermal desalination. The morphology, structure, absorbance and desalination performance of the rGO film are explored. It is found that rGO film with optimized microstructure delivers an evaporation rate of 0.87 kg m−2 h−1 with solar thermal conversion efficiency of 46% under 1 sun illumination. Moreover, the evaporation rate of rGO film remains at 0.86 kg/m2·h−1 after ten times recycling, demonstrating the superior reusability.

Research on polyvinylidene fluoride (PVDF) hollow-fiber hemodialyzer

2016 ◽  
Vol 61 (3) ◽  
pp. 309-316
Author(s):  
Qinglei Zhang ◽  
Xiaolong Lu ◽  
Lihua Zhao ◽  
Juanjuan Liu ◽  
Chunfeng Wu
Keyword(s):  
Mechanical Property ◽  
Hollow Fiber ◽  
Polyvinylidene Fluoride ◽  
Pure Water ◽  
Centrifugal Casting ◽  
High Flux ◽  
Pvdf Membrane ◽  
The Core ◽  
Middle Molecules ◽  
Hemodialysis Membrane

Abstract In this study, polyvinylidene fluoride (PVDF) hollow-fiber hemodialysis membranes were prepared by non-solvent-induced phase separation. The PVDF hollow-fiber hemodialyzers were prepared by centrifugal casting. The results showed that the PVDF membrane had better mechanical and separation properties when the membrane wall thickness was 40 μm and the N,N-dimethylacetamide in the core was 70 Vol%. Compared with commercial polysulfone hemodialysis membrane (Fresenius F60S membrane), the PVDF membrane had better mechanical property and ultrafiltration (UF) flux of pure water. The PVDF dialyzer’s removal efficiency for middle molecules was proven to be much higher than that of the F60S dialyzer. The UF coefficient of a high-flux PVDF dialyzer is 62.6 ml/h/mm Hg, whereas F60S is 42.5 ml/h/mm Hg, which can promote clearance for middle molecules.

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