CERAMICS INTERNATIONAL
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2019
·
IF 3.45
Yefeng Feng,Qihuang Deng,Cheng Peng,Qin Wu
Although high permittivity is achieved in barium titanate (BT) filled polymer nanocomposites , severely reduced insulation and breakdown properties are frequently found due to overload and agglomeration of BT nanoparticles with ultrahigh specific area. To simultaneously realize high permittivity and breakdown strength , in this work, unfunctionalized 2D Ti 3 C 2 MXene nanosheets with 2 wt% weight concentration were introduced to prepare ternary BT/MXene/polymer nanocomposites by solution cast process. Employing low-concentration conductive MXene instead of high-concentration ferroelectric BT could lead to significant improvement of permittivity of ternary composites, ascribed to remarkably increased interface types and enhanced interface polarization. In comparison to binary BT/polymer composites, ternary composites could have slightly improved dielectric loss and conductivity as well as gracefully reduced breakdown strength, attributed to finely retained high interface compatibility and filler dispersion. Ternary composite containing 8 wt% BT and 2 wt% MXene had a permittivity of 77, loss of 0.15 at 100 Hz and breakdown strength of 220 MV m −1 . This work might open the door to large-scale fabrication of promising composites with high permittivity and breakdown strength under low filler loading (~ 10 wt%).
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高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2019
·
IF 7.015
Haicheng Jiang,Qi Zhao,Panpan Wang,Jun Ma,Xuedong Zhai
Fabricating high-flux, low-fouling gravity-driven membranes (GDM) has proved to be an extremely challenging work. In this study, a novel tailored amphiphilic multi-arms polymer poly(propylene glycol)-silane-poly(ethylene glycol) (PPG-Si-PEG) was synthesized and blended into Polyvinylidene Fluoride (PVDF) matrix to fabricate GDM via nonsolvent induced phase separation method. The incorporation of multi-arms polymers affected phase separation and surface segregation behaviors, resulting in the formation of more porous structure, which were demonstrated by scanning electron microscopy (SEM). Moreover, the hydrophilic PEG arms in polymers were enriched onto membrane surface through surface segregation and utilized to improve the hydrophilicity of membranes, which were confirmed by Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The separation and antifouling properties of the membranes were evaluated by using gravity as the driving force, employing bovine serum albumin (BSA) as the model foulant. The water flux of membranes increased from 4.6 L m −2 h −1 for the control membrane to 12.1 L m −2 h −1 for PVDF/PPG-Si-PEG∼5% membrane. The antifouling properties of modified membranes were effectively improved in comparison with that of control membrane. The flux recovery ratio, especially for PVDF/PPG-Si-PEG∼5% membrane, was up to 99.4%. This study provided a new method for antifouling modification of GDM.
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CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2018
·Vol. 34
·期 6
·1051-1057
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IF 1.248
Dong Yanying,Yu Ping,Sun Qilong,Lu Yang,Tan Zhenjiang,Yu Xiaopeng
Effective molecularly imprinted membranes(MIMs) were developed as an efficient adsorbent for the selective removal of p -hydroxybenzoic acid( p -HB) from acetylsalicylic acid(ASA, aspirin). The MIMs were grafted successfully from poly(vinylidene fluoride) microfiltration membranes via reversible addition-fragmentation chain transfer(RAFT) polymerization. The graft copolymerization of acrylic acid(AA) in the presence of template p -hydroxybenzoic acid led to molecularly imprinted polymer(MIP) film coated membranes. The obtained MIMs were characterized by scanning electron microscopy(SEM), Fourier transform infrared spectrophotometer(FTIR) and Raman spectra, and batch mode adsorption studies were carried out to investigate the specific adsorption equilibrium, kinetics and selective recognition properties of different MIMs. The kinetic properties of the MIMs could be well described by the pseudo-second-order rate equation. Selective permeation experiments were performed to evaluate the permeation selectivity of the p -HB imprinted membranes. The observed performances of the MIMs are applicable to the further purification of aspirin.
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2015
·Vol. 33
·期 6
·857-868
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IF 1.835
Du Chun-hui,Ma Xu-min,Wu Chun-jin,Cai Mei-qiang,Hu Meng-xin,Wang Ting
Polymerizable ionic liquid copolymer P(MMA- co -BVIm-Br) was synthesized by radical polymerization technique, and characterized by Fourier transform infrared spectrometry (FTIR), 1 H Nuclear magnetic resonance ( 1 H-NMR) and gel permeation chromatography (GPC). The resulting copolymer was used to prepare poly(vinylidene fluoride) (PVDF) blend membranes via a phase inversion method. The effects of the copolymer on the polymorphism, surface wettability and zeta potential ( ζ ) of the blend membranes were investigated by ATR-FTIR, contact angle instrument and zeta potential analyzer. Scanning electron microscopy (SEM and SEM-EDS) was also applied to investigate the morphology and the surface element changes of the fabricated membranes. The results indicated that P(MMA- co -BVIm-Br) copolymer existed on the surface of the membrane which made the blend membrane have a positive surface during the experimental pH range. The copolymer was also in favor of the formation of β crystal phase in PVDF membranes. The contact angle experiment indicated that P(MMA- co -BVIm-Br) copolymer could switch the wettability of the blend membranes from hydrophilic to hydrophobic by exchanging Br − anion with PF 6
− . Compared with pure PVDF membranes, the water flux and water recovery flux of the blend membranes were enhanced obviously. The results from the flux recovery ratio (FR) and total fouling ratio ( R
t ) all suggested that the blend membranes had good anti-fouling properties.
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高影响因子
ELECTROCHIMICA ACTA
·
2014
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IF 4.086
Wei Zhai,Hua-jun Zhu,Long Wang,Xiao-min Liu,Hui Yang
The ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF 4 ) is selected as plasticizer to prepare a series of novel gel polymer electrolytes due to its non-volatility and inflammability. The micro-porous matrix employed in this study is poly(vinylidene fluoride-co-hexafluoropropylene)/poly(methyl methacrylate) (PVDF-HFP/PMMA) membrane synthesized via phase inversion. The effect of the ratio of PVDF-HFP to PMMA on the properties of the micro-porous membrane, such as morphology, porosity and the liquid uptake capability are systematically studied. Thermal and electrochemical properties of the resulting gel polymer electrolyte are also studied with the objective to optimize the quality of the micro-porous gel polymer electrolyte. The results indicate that the micro-porous gel polymer electrolyte MIL-60, derived from the matrix of PMMA-60 (40 wt% PVDF-HFP and 60 wt% of PMMA), presents the lowest glass transition temperature and exhibits the highest ionic conductivity . The LiFePO 4 /MIL-60/Li coin-typed cell cycled at 0.1 C shows the 1 st discharge capacity up to 157 mAh·g −1 , and remains 151 mAh·g −1 on the 50 th cycle.
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APPLIED SURFACE SCIENCE
·
2015
·
IF 2.711
Hongbin Li,Wenying Shi,Yufeng Zhang,Rong Zhou,Haixia Zhang
High modulus poly( p -phenylene terephtalamide) (PPTA) reinforced composites are of great scientific interests. But the thermodynamic difference makes the polymer pairs incompatible and endows the composites with inferior physical-chemical properties. In this study, hydrophilic poly(vinylidene fluoride) (PVDF)/poly( p -phenylene terephtalamide) (PPTA) blend membrane with improved hydrophilicity and mechanical strength was prepared through in situ polycondensation of p -phenylene diamine (PPD) and terephthaloyl chloride (TPC) in PVDF solution and subsequent immersion precipitation phase inversion process. The effects of PPTA concentration in polymer dopes on membrane formation process, structure, morphology and performance were systematically investigated. The results showed that thermodynamically, PPTA acted as a demixing enhancer which accelerated the phase inversion process. Dynamically, liquid-liquid phase separation was still in control of membrane formation process especially in the later period, whereas the addition of PPTA mainly promoted the early emergence of the liquid-liquid demixing. The surface hydrophilicity, ant-fouling properties and mechanical strength were significantly improved when PPTA content was 17 wt%. When PPTA content increased to 26 wt%, membrane bursting pressure increased to nearly 0.6 MPa which was 1.5 times higher than that of PVDF membrane. The resultant PVDF/PPTA blend membrane exhibited an improved antifouling property than that of PVDF membrane when applied in the MBR in the treatment of landfill leachate and also showed a relatively high removal rate of chemical oxygen demand (COD) and chrom.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2017
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IF 3.359
Ji-Hao Zuo,Peng Cheng,Xing-Fan Chen,Xi Yan,Ya-Jun Guo,Wan-Zhong Lang
Poly(vinylidene fluoride) (PVDF) membranes are prepared via thermally induced phase separation (TIPS) method with cold air as quenching air (PVDF T-air ), and surface-modified by polydopamine. The morphologies, surface chemistry, pore size, porosity, mechanical properties, separation performance in oil/water emulsion separation and antifouling ability of the prepared PVDF membranes were studied in detail. Compared with the PVDF membranes prepared by traditional TIPS method with cold water as quenching bath (PVDF T-water ), the PVDF T-air membranes are not only more environmental friendly and energy saving, but also show ultrahigh permeation flux without sacrificing oil rejections and improve mechanical strength. After being modified by polydopamine, the rich hydrophilic groups in dopamine endow the PVDF T-air membranes with excellent hydrophilic and underwater oleophobicity. The optimal membrane sample (M-3) shows a permeation flux of 3855.6 L·m −2 ·h −1 ·bar −1 for pure water and the ones above 2600 L·m −2 ·h −1 ·bar −1 for oil/water emulsions accompanied with above 98.5% oil rejections for three oil/water emulsions (n-hexane, toluene and petroleum ether). The results demonstrate that novel PVDF microfiltration membranes with ultrahigh permeation flux and oil rejection are prepared for oil/water emulsion separations.
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2017
·
IF 1.174
Kailiang Zeng,Jie Zhou,Zhaoliang Cui,Yue Zhou,Chuan Shi,Xiaozu Wang,Liyue Zhou,Xiaobin Ding,Zhaohui Wang,Enrico Drioli
Membrane fouling is the key problem that occurs in membrane process for water treatment. However, how membrane microstructure influences the fouling behavior is still not clear. In this study, fouling behavior caused by dextran was deeply and systematically investigated by employing four poly(vinylidene fluoride) (PVDF) membranes with different pore sizes, ranging from 24 to 94 nm. The extent of fouling by dextran was accurately characterized by pore reduction, flux decline, and the change of critical flux. The result shows that membrane with the smallest pore size of 24 nm experienced the smallest fouling rate and the lowest fouling extent. As the membrane pore size increased, the critical flux ranges were 105–114, 63–73, 38–44 and 34–43 L·m − 2 ·h − 1 , respectively. The critical flux and fouling resistances indicated that the fouling propensity increases with the increase of membrane pore size. Two pilot membrane modules with mean pore size of 25 nm and 60 nm were applied in membrane filtration of surface water treatment. The results showed that serious irreversible membrane fouling occurred on the membrane with pore size of 60 nm at the permeate flux of 40.5 L·m − 2 ·h − 1 . On the other hand, membrane with pore size of 25 nm exhibited much better anti-fouling performance when permeate flux was set to 40.5, 48 and 60 L·m − 2 ·h − 1 .
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高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2017
·
IF 6.035
Chen Li,Lei Wang,Xudong Wang,Mengxiao Kong,Quan Zhang,Guangyuan Li
Thermally induced graft copolymerization of sodium styrene sulfonate (SSS) with ozone-preactivated poly(vinylidene fluoride) (PVDF) produced a PVDF-g-PSSS copolymer . Sulfonic acid proton exchange membranes (PVDF-g-PSSA) were then prepared using the solvent evaporation method. They were investigated with a Fourier transform infrared spectrometer and an X-ray diffractometer. The results indicate that the proton conductivity of the prepared membranes reached 0.046 S/cm when the degree of grafting was 50.52%. Results from a quartz crystal microbalance with dissipation monitoring indicated that the PVDF-g-PSSA membrane showed superior antifouling performance to that of a Nafion membrane. The performance of the prepared membrane in dual-chamber microbial fuel cells was also evaluated and compared with that of Nafion 117. Although the microbial fuel cell with the prepared membrane generated lower maximum power density (106.7 mW/m 2 ) than that with Nafion 117 (132.0 mW/m 2 ), it was more cost-effective because of its lower price and more simplified preparation process. In addition, its chemical oxygen demand (COD) removal (85%) was much higher than that of Nafion 117 (74%).
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2017
·Vol. 41
·期 24
·14966-14976
·
IF 3.269
Juan Zhao,Yilin Wu,Shi Zhou,Li Yan,Hongjun Dong,Li Chen,Minjia Meng,Chunxiang Li,Yongsheng Yan
Antibiotic pollutants in water have received remarkable attention due to the untold damage to human health and the environment, yet no approach has been used to solve the problem effectively. In this work, novel and efficient norfloxacin-molecularly imprinted composite membranes with an organic–inorganic structure (NFIcMs) were designed and developed using GO/PVDF blended membranes as substrates for selective separation and fast enrichment of norfloxacin from aqueous solution. The selectivity coefficient (α) of NFIcMs was up to 7.35 and more than 1.0, and the permeability factor β values were about 6.0 and more than 1.0, which indicated that the as-prepared NFIcMs possessed outstanding selectivity and permeability. Moreover, the synergistic effects of the specific surface area of GO, fouling resistance of TiO2 and high mechanical strength of PVDF membranes resulted in the fact that NFIcMs had a high adsorption capacity (44.81 mg g−1) for norfloxacin. Additionally, the facile and eco-friendly preparation of the demonstrated NFIcMs rendered them with the application potential in the treatment of antibiotic pollutants.
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高影响因子
DESALINATION
·
2024
·
IF 8.3
Wenting Li,Mengdi Chen,Ganwei Zhang,Weicai Chen,Lei Zhang,Shusu Shen,Dapeng Liu,Xiaoji Zhou,Yaoliang Hong
The DCMD technology for wastewater treatment is very promising. However, it is easily suffered by membrane fouling and wetting. In this study, a Janus membrane was fabricated by coating polyvinylamine (PVAM) and gallic acid (GA) onto one side of a PVDF composite membrane, which another side is covered with POTS-SiO 2 . The PVAM and GA side could bind water to form a hydration layer, thus repel the contaminants. The POTS-SiO 2 side was superhydrophobicity and prevented the membrane wetting. Finally, The Janus membrane presented exceptional performance in separating salt containing emulsified oil by DCMD. It kept a stable flux of 17.0 ± 0.2 Kg·m −2 ·h −1 and a low level conductivity of 0.60 ± 0.02 μS/cm in the cold side during the 36 h DCMD procedure, compared with the pristine PVDF membrane and the PVDF/POTS-SiO 2 membrane. The results presented simultaneously antifouling and antiwetting properties of the Janus membrane. While the Janus membrane can be well used in desalination of emulsified oil containing salt, it has a great potential for application to treat other complex wastewater.
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ENERGY & FUELS
·
2024
·
IF 5.2
Jingyi Sun,Dingbo Han,Ruiguo Dong,Jing Ge,Shuzhen Li,Han Guo,Ce Wang,Ping Hu,Yong Liu
Proton exchange membranes often encounter challenges with proton conductivity and dimensional stability under conditions of high temperature and low humidity. Incorporating proton-conductive nanofibers into the membrane fortifies its dimensional stability and establishes extra proton transfer channels at the interface between the fibers and matrix, thereby improving proton conductivity. This study utilized polyvinylidene fluoride (PVDF) fibers as a base material, modified with ethylenediamine to yield amine-functionalized cross-linked structures. UiO-66-NH2 and UiO-66-NH2–SO3H were then grown in situ on these fibers, and the resultant structures were integrated with Nafion to fabricate metal–organic framework (MOF)-modified nanofiber proton exchange membranes (NFPEMs). We examined the growth of MOFs and their role in enhancing the nanofiber proton exchange membrane’s properties. Both UiO-66-NH2 and UiO-66-NH2–SO3H were successfully incorporated, resulting in a maximum enhancement of proton conductivity by 149.69 and 80.38%, respectively, compared with PVDF@Nafion, and the proton conductivity of the MOF-loaded membrane reaches 152.11 ms/cm at 80 °C and 100% relative humidity. The swelling rates were also significantly reduced by up to 59.16 and 57.94%, relative to Nafion, effectively boosting dimensional stability and thermal stability. These improvements are attributed to the additional proton transfer channels formed by the MOFs, the contribution of acid–base pairs, limitations imposed by MOF porosity on water molecule mobility, and the supportive three-dimensional network conferred by PVDF. Findings from this research provide valuable guidance for the design of NFPEMs.
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危险品化学品经营许可证（带存储）