JOURNAL OF MEMBRANE SCIENCE
·
2019
·
IF 7.015
Wei Zhang,Yubing Lu,Jun Liu,Xipeng Li,Baoan Li,Shichang Wang
Superhydrophobic and oleophobic membrane applied in membrane distillation was fabricated by constructing a re-entrant composite structure via immobilizing silica nanoparticles (NPs) on the polyvinylidene fluoride (PVDF) membrane. The silica coated membrane with the assistance of polydopamine (PDA) was then fluorosilanized by means of a silane coupling agent 1H,1H,2H,2H-perfluorooctyltrichlorosilane. A series of characterizations were implemented to investigate the effects of modification process on the structure and performance of the PVDF composite membranes . The fouling and wetting behaviors of original and modified membranes were explored by direct contact membrane distillation (DCMD) tests using a mixed solution of inorganic salts, organic matter and surfactant as the feed. The results indicated that silica NPs and fluorinated silane were presented on the PVDF membrane substrate. After surface modification, the liquid entry pressure (LEP) increased by 120%, in addition, the water contact angle (WCA) increased from 127.0° to 169.0°, and the oil contact angle (OCA) increased from 2.8° to 112.1°. The modification process showed no effect on the pore size and pore structure . Furthermore, the composite membrane exhibited excellent chemical stability and prominent mechanical stability. The re-entrant structure resulting from nanoparticles and microspheres and the omniphobic feature were conferred on the composite membrane. The DCMD tests showed that the composite membrane kept a stable permeate flux in the long-term concentration experiment, with the salt rejection rate approximately 100%. What's more, the composite membrane did not suffer from fouling and wetting, and still dry and clean after the test. In comparison, the pristine membrane was seriously polluted during the test, and the permeate flux decreased to 28.3% of the initial value. Overall, the novel modified PVDF composite membrane reported in this work presents outstanding anti-fouling performances.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 13
·6108-6119
·
IF 3.591
Siyi Li,Xuehui Zhao,Hongwei Zhang
It is very important to reduce the oxidation of free radicals in organic membrane materials for the stability and safety of drinking water production treatment processes. This paper presents a new method for the qualitative and quantitative determination of free radicals in sodium hypochlorite solution by electron spin resonance (ESR) and salicylic acid spectrophotometry. Experiments show that the free radical scavenging rate reaches over 86% after the addition of 0.5 wt% nano-particles. PVDF–PVP/TiO2 and PVDF–PVP/CNT modified membranes are prepared by blending polyvinylidene fluoride (PVDF) with nano titanium dioxide (nano-TiO2) and carboxyl-modified multi-wall carbon nanotubes (MWCNTs-COOH), and are treated in 2000 ppm sodium hypochlorite solution for 30 days. Through surface chemistry (FTIR, XRD), surface morphology (SEM), surface hydrophilicity (contact angle), surface electronegative (zeta potential) and mechanical properties tests, the changes of membrane properties are analyzed during aging. The experimental results show that the nano-particles have a quenching effect on free radicals and inhibit defluorination. It has been proved that under the action of nano-additives, the erosion of free radicals on the membrane material is reduced, the aging rate of the membrane material is decreased, and the chemical stability of the membrane material is improved. In this paper, the reason and mechanism of anti-aging of the nano-particle modified membrane are analyzed, which provides theoretical support for future membrane cleaning technology and prolonging the service life of the membrane.
研究领域:
材料科学
·
环境工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Energy Materials
·
2022
·
IF 6.959
XiaoYa Hao,Qiong Fu,YaFei Hou,YuanJie Yan,TingYu Fu,Jing Cuan,Peng Du,LaiHui Luo,WeiPing Li
Both high discharge energy density (Ud) and charge–discharge efficiency (η) for nanocomposites are crucial to the development and application of modern electronic devices. However, the large dielectric contrast and ferroelectric phase greatly limit the improvement of Ud and η of poly(vinylidene fluoride) (PVDF)-based nanocomposites. Herein, Bi2O2CO3 (simplified as BOC) nanosheets with low dielectric constant and wide bandgaps and linear poly(methyl methacrylate) (PMMA) were filled into PVDF by solution casting to fabricate x vol % BOC/PAPF (PAPF is short for PMMA/PVDF) nanocomposites. The contributions of BOC nanosheets and linear PMMA, especially for the BOC nanosheet, have been systematically studied. Both experimental and simulation results show that BOC nanosheet and PMMA could improve the breakdown strength and reduce the dielectric loss and leakage current of nanocomposites simultaneously, realizing Ud and η improvement at the same time. As a result, the 1.0 vol % BOC/PAPF nanocomposite shows the highest energy storage performance with Ud = 13.68 J/cm3 and η = 85.72%, which is much superior to PVDF. Therefore, this study might provide a proof-of-concept for constructing nanocomposites with excellent Ud and η concurrently.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
Desalination and Water Treatment
·
2024
·
IF 1
Xiaoting Zhang,Runping Han
ABSTRACT A novel film adsorbent (PVDF-PEI) was prepared by simple blending polyethyleneimine and polyvinylidene fluoride for efficient uptake Cu(II) and Pb(II) from solution. The characterization of PVDF-PEI was investigated by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. Moreover, the effect about adsorbent mass, solution pH, salinity, contact time, temperature and initial Cu(II) and Pb(II) concentrations was researched by batch experiments, respectively. The adsorption quantity of Cu(II) and Pb(II) was to 81.3 and 178 mg g –1 from Langmuir model under the solid-liquid ratio was 0.5 g L –1 for 8 h at 303 K. Freundlich model and Koble–Corrigan mode well predicted the adsorption isotherms while pseudo-first-order and Elovich models appropriately described the adsorption kinetic curves. The thermodynamic parameters illustrated that both processes were endothermic and spontaneous reactions with increased entropy. Cu-loaded PVDF-PEI and Pb-loaded PVDF-PEI were better regenerated by using 0.1 mol L –1 HCl and HNO 3 , respectively. The mechanisms were both complexation and ion exchange. Overall, it is referred that PVDF-PEI be promising for eliminating Cu(II) and Pb(II) from wastewater.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
DESALINATION
·
2017
·
IF 5.527
Heiyan Zhang,Bingbing Li,De Sun,Xiaoling Miao,Yunlei Gu
In this study, hydrophobic asymmetric SiO 2 -PDMS-PVDF hollow fiber membranes were prepared for the vacuum membrane distillation (VMD). To make PVDF dope solution, hydrophobic nano-fumed silica (SiO 2 ) and polydimethylsiloxane (PDMS) were used. The effects of SiO 2 concentration on membrane parameters such as membrane morphology, hydrophobicity , porosity, thickness, pore size, liquid entry pressure , burst pressure, Fourier transformed infrared spectroscopy , thermal property, mechanical property and permeability were investigated. With the increasing of nano-particle concentration, membrane hydrophobicity, mechanical property and thermal stability improved. Furthermore, membrane VMD properties under various operation conditions were studied, the membranes showed a stable substantial flux of 44.27 LMH and a stable high salt rejection of over 99.9% under the optimum operation conditions of 75 °C, 35 g/L, 87 kPa, and 50 L/h. The results of our research demonstrated that the prepared hydrophobic asymmetric SiO 2 -PDMS-PVDF hollow fiber membranes not only had high permeability and good anti-wetting property but also exhibited a satisfying stability for the vacuum membrane distillation of desalination .
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2015
·
IF 3.091
Daqing Tong,Xiaozu Wang,Mohammad Ali,Christopher Q. Lan,Yong Wang,Enrico Drioli,Zhaohui Wang,Zhaoliang Cui
Hydrophobic membrane is desired to avoid pore wetting phenomenon in membrane distillation (MD). In the present paper, highly hydrophobic Hyflon AD60/PVDF composite hollow fiber membranes were prepared by coating a copolymer (Hyflon AD60) of tetrafluoroethylene (TFE) and 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole (TTD) on poly(vinylidene fluoride) (PVDF) membranes. The effects of Hyflon AD60 concentration, coating time, heat-treatment temperature and heat-treatment time on the structures and performances of Hyflon AD60/PVDF composite hollow fiber membranes in vacuum membrane distillation (VMD) process were investigated. The results show that the hydrophobicity of PVDF hollow fiber membrane was significantly improved by coating Hyflon AD60. The optimized Hyflon AD60 concentration, coating time, heat-treatment temperature and heat-treatment time were 0.1 wt%, 10–20 min, 40–50 °C and 9 h, respectively. Employing NaCl solution with concentration of 35 g × L −1 , under a vacuum of 0.09 MPa and feed temperature of 70 °C, the water flux and salt rejection of the composite hollow fiber membrane in VMD process reached to approximately 10 kg × m −2 × h −1 and higher than 99.9 %, respectively, and kept stable, indicating that Hyflon AD60/PVDF composite membrane is an excellent candidate for operation in VMD operation.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Communications
·
2022
·
IF 3.662
Ruitian Bo,Jihua Wang,Chunfeng Wang,Yongliang Wang,Peigang He,Zhidong Han
The selective distribution of inorganic particles in polymer blends is of great significance in designing the composites with excellent properties such as dielectric properties . Molecular dynamics (MD) was applied in this paper to simulate the distribution of BaTiO 3 (BT) and graphene nanoplatelets (GNP) in polystyrene/polyvinylidene fluoride (PS/PVDF) blends. The models of PS and PVDF were built and the phase structure of the blends was simulated at the different PS/PVDF mass ratios. According to the results of solubility parameter and Flory-Huggins interaction parameter (χ), the immiscibility between PS and PVDF was illustrated and the phase transition phenomena were predicted. Combined with the SEM observations, the co-continuous structure of the blend at the PS/PVDF ratio of 6/4 was obtained at the maximal χ value. The binding energy and radial distribution function were calculated to predict the selective distribution of BT or GNP in PS/PVDF blends. According to the results of the MD simulations, the distribution of BT in the PVDF phase and GNP in the PS phase were successfully predicted, which were in good agreement with the experimental results by SEM observations and EDS element mapping. The MD simulations would be effective in building the co-continuous immiscible blends and predicting the selective distribution of functional fillers, which will be helpful for the investigation of functional composites with high performance.
研究领域:
材料科学
·
计算化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Hongbin Li,Hengji Liu,Wenying Shi,Haixia Zhang,Rong Zhou,Xiaohong Qin
Mixed matrix membranes (MMMs) combine the advantages of different materials and hopefully break through the limitation of high mass transfer resistance and low permeability in membrane distillation (MD) process. In this study, hydrophobic zeolitic imidazolate framework-71 (ZIF-71)/polyvinylidene fluoride (PVDF) hollow fiber composite membrane was prepared by the dilute solution coating method. ZIF-71 was incorporated into the PVDF dilute solution and a macroporous hydrophobic ZIF-71/PVDF coating layer was formed on the outer surface of PVDF hollow fiber support membrane through the nonsolvent induced phase separation (NIPS) process. PVDF hollow fiber support membrane was fabricated by the dry-jet wet spinning process. Membrane surface morphologies were observed through Field emission scanning electron microscope (FESEM). The effects of zeolitic imidazolate frameworks (ZIFs) content in PVDF coating layer on membrane surface hydrophobicity and desalination performance were investigated through Dynamic water contact angle (WCA) measurements and the vacuum membrane distillation (VMD) experiment, respectively. The VMD experiment was carried out at feed temperature 50 °C and permeation side vacuum 31.3 kPa using 3.5 wt% NaCl aqueous solution as the feed solution. Compared with the uncoated PVDF hollow fiber membrane, both the surface hydrophobicity and the water permeability of the ZIFs-incorporated PVDF hollow fiber composite membranes are improved. The surface WCA and permeation water flux of ZIFs-PVDF composite membrane increase from 94.5 to 136.5° and 13.5 to 27.1 kg . m −2. h −1 meanwhile the NaCl rejection could maintain at 99.99%. No obvious pore wetting phenomenon was observed for ZIFs-PVDF hollow fiber composite membrane during the continuous VMD experiment for 60 h. The dilute solution coating is a promising method to prepare high-performance hollow fiber composite membrane for the desalination in MD process.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2025
·
IF 3.1
Yang Zhan-jun,Liu Hao,Das Oisik,Wang Xiao-qian,Li Mi,Han Zhong-xuan,Jiang Lin,Rotaru Andrei
This study contributes to advancing research in aluminium alloys employed as fuels for thermites (pyrotechnic compositions formed of metal and metal oxide powders). Aluminium alloys possess certain potential in regulating energy release and enhancing combustion efficiency; in order to explore better formulations for the aluminium alloy fuel thermite, PVDF-coated Al–Si samples with different proportions were prepared here by using the electrostatic spraying method. In this study, we are primarily addressing the energy release limitation problems which are imposed by the oxide layer formation during the combustion of aluminium–silicon alloy powders in air and explore the optimal formulation of aluminium–silicon fuel combined with fluoropolymer oxidants. Leveraging advanced electrostatic spraying technology, various PVDF (polyvinylidene fluoride)-coated Al–Si samples (Al–Si@PVDF) were successfully synthesized. Morphological characterization confirmed the complete encapsulation of Al–Si alloy powders by PVDF, yielding spherical core–shell structures with uniform elemental distribution and favourable microstructural characteristics. Further, by thermal analysis and calorimetry investigation, a two-stage reaction between Al–Si and PVDF was unveiled: an initial PVDF decomposition phase followed by an ignition reaction phase. To comprehensively evaluate the combustion performance of samples with varying proportions, high-speed and infrared cameras were employed for precise observations, enabling a deep dive into the combustion parameters and their disparities under two distinct spatial conditions. Through these combustion performance experiments and post-combustion product analysis, we deduced the micro-combustion process mechanism of Al–Si@PVDF. This works not only that it provides a scientific basis for optimizing the formulation of aluminium–silicon fuels and fluoropolymer oxidants, but also holds positive implications for advancing research and development in aluminium alloy-based metastable intermolecular composites. Last but not least, besides the high combustion rates, low ignition temperatures, stable combustion, and strong exothermic performance were obtained for these thermite composite materials.
研究领域:
材料科学
·
燃烧学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Zongting Zhu,Yi Tian,Yibin Liu,Kang Fu,Qianwen Chen,Baoliang Zhang,Hepeng Zhang,Qiuyu Zhang
Development of superhydrophobic coatings is restricted by –their poor durability and complicated preparation process. Herein, we prepared a simple and efficient protocol to synthesize a superhydrophobic coating with excellent mechanical properties and durability for large-scale application. Initially, the free radical polymerization of methyl methacrylate (MMA), glycidyl methacrylate (GMA) and heptadecafluorodecyl acrylate (HFA) were carried out to prepare polymer PGMH. PGMH was then mixed with poly(vinylidene) fluoride (PVDF) to finally form the PGMH-PVDF superhydrophobic coatings. During solvent vapor annealing, fluoroalkyl groups and PVDF clusters tended to migrate to solid-gas interface and enriched the coating surface. The self-assembly behavior of PVDF clusters was attributed to good compatibility of PVDF clusters with HFA segments in blending system. In addition, MMA and GMA segments in PGMH deposited at the bottom to provide mechanical strength and substrates adhesion. Besides, the prepared superhydrophobic coatings demonstrated outstanding abrasion resistance for up to 100 sandpaper abrasion. In addition, the superhydrophobic coatings also exhibited exceptional chemical stability and self-cleaning property. The static anti-icing characterizations confirmed that the PGMH-PVDF films possessed good icing-delaying ability. Therefore, the superhydrophobic coatings would have tremendous potential applications in the field of waterproof, self-cleaning, and anti-icing surfaces.
研究领域:
材料科学
·
表面工程
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2021
·
IF 5.909
Wanying Xie,Ji Li,Feiyun Sun,Wenyi Dong,Zijun Dong
Aiming at the fouling problem of PVDF membrane, one novel integrated strategy was used for the first time, including hydrophilic membrane modification and low-pressure operation. Permeability and anti-fouling ability of PVDF were simultaneously improved by nano-TiO 2 embedment. From perspective of operating condition optimization, the concepts of critical flux (J C ) and threshold flux (J TH ) were recommended as fouling-control tools. The J C and J TH of PVDF-TiO 2 membrane were tested by two constant pressure-steps methods, i.e. Constant pressure-step method and Alternating constant pressure-step method. Three indicators, consisting of instant FTTT curves, dFlux/dt condition and TMP-Flux ave curve, were employed to evaluate the J C and J TH of PVDF-TiO 2 membrane. In brief, the J C and J TH of PVDF-TiO 2 were 10.62 and 23.91 L/(m 2 ·h), respectively, which were nearly 3 times of PVDF membrane. Fouling resistance results displayed that protein irreversible fouling of two PVDF membranes were effectively reduced by J C mode and J TH mode. Besides, reversible fouling of PVDF-TiO 2 membrane was controlled well by J C mode meanwhile. The pure water filtration line (PWF line) and the normalized resistance were both used to judge the form of J C of two membranes. As compared with PVDF, it was speculated the enhancement of J C and J TH mainly related to the better hydrophilicity and local hydraulic condition of PVDF-TiO 2 modified membrane.
研究领域:
环境科学
·
材料科学
·
生物工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Electronic Materials
·
2022
·
IF 4.494
Cheng Han,Lirong He,Qi Wang,Chuhong Zhang
Three-dimensional (3D) printing technologies possess incomparable advantages in fabricating 3D piezoelectric devices, enhancing the mechanical-to-electrical conversion efficiency. Among them, direct ink writing (DIW) holds great promise in constructing piezoelectric polymer devices as it enables self-polarization benefiting from the alignment of dipoles induced by the high pressure during the printing process. Besides, the electroactive phase of piezoelectric polymers is retained due to the operation is under ambient conditions. However, for the generally applied solvent-evaporation-assisted DIW technique, the architected structure suffers from drastic shrinkage and warpage in the final parts, which ultimately leads to a significant deviation from the programmed measure. In this work, for the first time, we develop a solvent-exchange-assisted DIW printing strategy to architect accurate and stable 3D PVDF PEH. This solvent exchange process in water not only enables the complete retaining of filament measure and generation of micropores to amplify the stain but also promotes the PVDF crystallization and formation of the β-phase. Moreover, trace vitamin B2 is formulated into the ink, affording self-polarized high β-phase content (95%) PVDF with good printability and optimal storage modulus to hold the 3D shapes. As a result, the 3D printed PVDF delivers an output voltage of 17.8 V, increased by 304% compared with device fabricated by solvent-evaporation-assisted DIW technique, and an impressive area output voltage density (11.04 V cm–2) which is twice that of the reported DIW printed PVDF PEH. This facile approach demonstrates a potential roadmap to high performance PEH through exploring complex 3D geometries enabled by the solvent-exchange-assisted 3D printing technique.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）