ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
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2020
·
IF 4.872
Xiarong Zheng,Yuanqiong Liu,Xiaobin Liu,Qingbiao Li,Yanmei Zheng
A novel composite electrospun fiber with high photocatalytic efficiency, good stability, strong hydrophobicity, good pollution resistance, and easy separation and recovery was synthesized. The TiO 2 @g-C 3 N 4 (TCN) with special core-shell structure (5–10 nm shell) facilitated the separation of photogenerated electron-holes and had high photocatalytic performance. The poly (vinylidene fluoride) (PVDF) electrospun fiber immobilized with TCN was successfully fabricated (PVDF-TCN) with uniform distribution and size of nanofibers by using electrospinning, which was used for degrading tetracycline under visible-light irradiation (> 400 nm). A special rougher surface of electrospun fiber obtained by washing of sacrificial PVP increased the specific surface area, which became more conducive to the adhesion of the catalyst. The water contact angle and FTIR results demonstrated that the electrospun fiber became extremely hydrophilic after adding TCN catalyst, which could effectively mitigate the fiber pollution. The PVDF-TCN-0.2g electrospun fiber exhibited excellent photocatalytic performance and the degradation efficiency of tetracycline was up to 97% in 300 min under visible-light irradiation. The mechanism of PVDF-TCN electrospun fiber degradation of tetracycline in the photocatalytic process was also proposed. In addition, the PVDF-TCN-0.2g exhibited a stable activity after 4 cycles experiments since the degradation efficiency remained about 90%. Therefore, we believed this study provided a new strategy in catalyst immobilization and wastewater treatment.
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高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2020
·
IF 7.183
Jiayun Zhu,Shouyong Zhou,Meisheng Li,Ailian Xue,Yijiang Zhao,Wenbo Peng,Weihong Xing
A novel PVDF mixed matrix ultrafiltration membrane was prepared by blending PVDF with the deformed rebar-like Fe 3 O 4 –palygorskite nanocomposites (MPGS) using the chemical coprecipitation method. Fe 3 O 4 nanoparticles were anchored on the surface of the palygorskite nanofibers to form deformed rebar-like structures. MPGS were then distributed uniformly on the membrane matrix. PVDF chains firmly wrapped by the deformed rebar-like nanocomposites consequently enhanced the tensile strength of the PVDF membrane. At 7.0 wt % MPGS, the tensile strength increased from 1.59 MPa to 2.66 MPa. The overall thickness, skin layer thickness, finger-like voids, average pore size and surface roughness of membranes decreased with increasing amounts of MPGS. The rejection of the membrane increased to 99.09% at 7.0 wt % MPGS. The contact angle of membranes decreased from 99.14° (pure PVDF) to 78.76° (PVDF/7.0 wt % MPGS). On the other hand, the pure water flux of membranes increased from 123.57 L m −2 h −1 (pure PVDF) to 356.16 L m −2 h −1 (PVDF/7.0 wt % MPGS). The flux recovery rate of the mixed matrix membranes (PVDF/7.0 wt % MPGS) was as high as 80%. This was more than twice that of the pure PVDF membrane (31.6%). These results demonstrated that the deformed rebar-like structure of the MPGS played a critical role in determining the structures and properties of PVDF mixed matrix ultrafiltration membranes. The hydrophilicity, thermal stability, permeation flux and antifouling property of the mixed matrix membranes increased with addition of MPGS. As such, PVDF/MPGS membranes had excellent comprehensive properties thus making them ideal for application in numerous fields.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 19
·8403-8419
·
IF 3.553
Zhang Yuhui,Lin Ligang,Wang Qi,Qiang Rongrong,Gao Yixin,Ma Sisi,Cheng Qi,Zhang Yuzhong
A new strategy was proposed that simultaneously improves the pervaporation (PV) performance and solvent resistance via the construction of a movable crosslinked structure in ethyl cellulose/polyvinylidene fluoride (EC/PVDF) composite membrane for the purpose of benzene/cyclohexane separation. Based on the molecular design of the macrocyclic compound cyclodextrin, polyrotaxane crosslinking agent (PR=) with a special sliding/rotating property and cavity structure was successfully synthesized. Furthermore, for convenient comparative study, cyclodextrin crosslinking agent (CD=) with cavity structure bereft of a sliding/rotating property and pentaerythritol triacrylate (PETA) without sliding/rotating property and cavity structure were prepared. The composite membranes were fabricated with crosslinking modified EC as active layer, together with PVDF support layer. The molecular structure and microstructure were confirmed. The pervaporation and swelling performance of the fabricated membranes for benzene/cyclohexane were investigated. PR= modified membranes showed good solvent resistance and exhibited a flux of 4332 g·m −2 ·h −1 and separation factor of 6.26, which was higher than CD= and PETA modified membranes. The results were attributed to the facilitated transport behavior, which was markedly related with the sliding/rotating property and cavity structure of polyrotaxane (PR). The related research provides interesting suggestions for PV membrane design for the separation of organic mixtures.
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高影响因子
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
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2020
·
IF 3.306
Jinying Du,Ning Li,Yu Tian,Jun Zhang,Wei Zuo
A novel composite membrane was prepared successfully by blending polyvinylidene fluoride (PVDF) with the synthesized graphene oxide-zinc sulfide (GO-ZnS) nanocomposites via phase inversion method. The dispersion of GO-ZnS and its effect on the performance of the PVDF membrane were investigated using the morphology, crystal structure and chemical composition of the composite PVDF membrane. With the content of GO-ZnS in the PVDF membrane increasing from 0 to 5.0 wt%, the contact angle declined continuously and thus the hydrophilicity of membrane increased after modification. Similarly, the pure water flux of GO-ZnS/PVDF membrane reached up to 431.9 L/(m 2 h) when 5.0 wt% GO-ZnS was blended. All membranes presented a high bovine serum albumin (BSA) removal and the rejection was about 86.5%. More importantly, the GO-ZnS/PVDF membrane exhibited a smaller irreversible fouling ratio and a higher flux recovery rate, revealing that blending with GO-ZnS could improve the self-cleaning under UV irradiation and the antifouling properties of PVDF membrane.
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高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2019
·
IF 3.218
Lanlan Tian,Mengkun Wang,Lian Xiong,Chao Huang,Haijun Guo,Shimiao Yao,Hairong Zhang,Xinde Chen
Poly (methyl methacrylate) (PMMA) based gel electrolyte has excellent chemical stability and low interfacial resistance but its mechanical strength is poor. In this study, organic palygorskite modified PMMA (p(OPal-MMA)/poly(vinylidene fluoride)) (PVDF) blend based electrolyte membrane was prepared via phase inversion casting technique. The physical and electrochemical properties of the blend membrane were investigated by XRD, SEM, tensile test and electrochemistry workstation. The results showed that PVDF can significantly improve the mechanical strength. The crystal phase of PVDF disappeared after blending. The porosity and ionic conductivity of the p(OPal-MMA)/PVDF membrane was 57.73% and 4.93 × 10 −3 S/cm respectively. The electrochemical stability window of Li/gel B-PVDF electrolyte/SS cell was stable up to 4.7 V (vs. Li + /Li), and the cell of Li/gel B-PVDF 43% electrolyte/LiFePO 4 exhibited good cycling performance and the Coulombic efficiency was maintained above 98.5% during all the cycling process.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Guangfa Zhang,Yuzhen Li,Ailin Gao,Qinghua Zhang,Jian Cui,Shuai Zhao,Xiaoli Zhan,Yehai Yan
Exploiting high-performance polymer membranes, which can simultaneously remove of both highly-emulsified oils and water-soluble contaminants such as dyes, is urgently required, yet remains an arduous challenge due to the critical restrictions of single functionality and severe membrane fouling. Herein, a superior superwettable polyvinylidene fluoride/chitosan/dopamine (PVDF/CS&DA) membrane was developed via a facile one-step codeposition strategy. With the catalysis of tyrosinase, DA-based chemical modification was conducted in a weak acid environment (pH 5.8–6.0) rather than conventional alkaline environment (i.e., pH 8.5), providing an intriguing alternative route towards mussel-inspired functional modification. Owing to the synergistic effect of the hydrophilic components and nano-structure roughness, the resultant membrane exhibited remarkable underwater superoleophobicity (oil CA of 1, 2-dichloroethane, 163.9°) and oil-repellency properties. Accordingly, benefiting from the superwettability features, the composite membrane achieved superior separation (an enhanced permeation flux of 201.3 L m −2 h −1 and a high separation efficiency of up to 99.7%) and anti-fouling performances in separating oil-in-water emulsions. More interestingly, this membrane displayed an excellent in situ adsorption capability for water-soluble anionic dyes, showing a fairly high adsorption efficiency (96.8% and 92.7% for methyl blue and orange G, respectively) after merely one-time rapid filtration and a robust recyclability. Therefore, the resulting membrane integrating high-efficiency emulsions separation and synchronous dyes removal capabilities holds a great prospect for sophisticated oily wastewater decontamination.
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高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2019
·
IF 7.015
Xipeng Li,Huiting Shan,Min Cao,Baoan Li
Omniphobic membranes have been brought to great attention recently regarding the ability to resist both water and low surface tension liquids, thus can be utilized for desalination of saline wastewater containing low surface tension contaminants in membrane distillation (MD). In this study, a facile, environment-friendly, and one-step strategy is developed for fabricating an omniphobic membrane with re-entrant structure and low surface energy by spraying a waterborne coating solution comprising of fluorocarbon surfactant (FS, Zonyl@8867L), fluorinated alkyl silane (FAS), and silicon dioxide nano-particles (SiO 2 NPs) onto amino functionalized polyvinylidene difluoride (PVDF) membrane via electrostatic adsorption. As a result, the prepared omniphobic FS/FAS/Si membrane possesses high liquid repellency to water, diiodomethane, mineral oil-in-water emulsion (0.10 % v/v), mineral oil, and SDS solution (0.40 mM) with the contact angle of 164.40 ± 0.95°, 159.12 ± 3.12°, 154.31 ± 3.71°, 153.31 ± 2.09°, and 157.14 ± 3.29°, respectively. Compared to the original PVDF membrane, the omniphobic FS/FAS/Si membrane displays higher rejection (about 99.99%) and superior anti-wetting and anti-fouling characteristics even to the saline feed solution with surfactants, oil pollutants, or hydrophilic organic pollutants in MD process. The results mentioned above verify that the obtained omniphobic FS/FAS/Si membrane has potential application for the desalination of the high saline wastewater containing low surface tension contaminants.
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高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2020
·Vol. 27
·期 9
·9503-9519
·
IF 3.056
Xie Wanying,Li Ji,Sun Feiyun,Dong Wenyi
The influence of ultrasonication on membrane performance was investigated by two ultrasonication modes, direct and indirect ultrasonication as pretreatment, and simply improved PVDF-TiO 2 membranes’ performance was systematically compared. Ultrasound intensity of 100% and ultrasonication time ranged from 1 to 2 h positively affect membrane permeability. Characterization results manifested that membrane structure was eventually optimized with an even nano-TiO 2 dispersion by direct ultrasonication. Analysis of surface roughness reflected that PVDF-TiO 2 (MS-U2) surface morphological pattern was peak-valley structure that resisted fouling greatly. A good fitting of experimental result and Tansel’s simulation illustrated that anti-fouling ability was realized direct ultrasonication modified membrane. PVDF-TiO 2 (MS-U2) membrane showing the lowest | τ | reflecting the time required to reach a certain level of the fouling degree was the lowest. Relying upon modified Hermia’s model analysis, protein blockage within the membrane pore was one major fouling mechanism; surface blockage degree of PVDF-TiO 2 (MS-U2) was relative slight. Fouling mechanism analyzed by two models reflected that PVDF-TiO 2 (MS-U2) membrane exhibited a higher anti-protein fouling ability during cross-flow filtration process.
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高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2018
·Vol. 28
·期 40
·1804121
·
IF 13.325
Yuzhang Zhu,Jinliang Wang,Feng Zhang,Shoujian Gao,Aqiang Wang,Wangxi Fang,Jian Jin
Fouling caused by oil and other pollutants is one of the most serious challenges for membranes used for oil/water separation. Aiming at improving the comprehensive antifouling property of membranes and thus achieving long-term cyclic stability, it is reported in this work the design of a kind of zwitterionic nanosized hydrogels grafted poly(vinylidene fluoride) (PVDF) microfiltration membrane (ZNG-g-PVDF) with superior fouling-tolerant property for oil-in-water emulsion separation. Sulfobetaine zwitterionic nanohydrogels with the diameter of ≈ 50 nm are synthesized by an inverse microemulsion polymerization process. They are then grafted onto the surface of PVDF microfiltration membrane, endowing the membrane a superhydrophilic and nearly zero oil adhesion property. This ZNG-g-PVDF membrane exhibits great tolerance and resistance to salts pH, especially an excellent antifouling property to oil-in-water emulsions containing various pollutants such as surfactants, proteins, and natural organic materials (e.g., humic acid). The comprehensive antifouling property of the membrane gives rise to the cyclic stability of the membrane greatly improved. A nearly 100% recovery ratio of permeating flux is achieved during several cycles of oil-in-water emulsion filtration. The ZNG-g-PVDF membrane shows great potential in treating practical oily wastewater containing complicated components in the effluent.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Jinling Lv,Guoquan Zhang,Hanmin Zhang,Fenglin Yang
The graphene oxide-cellulose nanocrystal (GO-CNC) composites were facilely synthesized and used as a novel hydrophilic additive to blend into poly(vinylidene fluoride) (PVDF) microporous membrane aiming at improving the antifouling performance of the resultant GO-CNC/PVDF membrane in MBR. The physicochemical properties of the GO-CNC composite and its functionalized PVDF membrane were investigated in detail by SEM-EDX, FTIR, XRD, water contact angle, zeta potential, permeability and fouling analysis. Results revealed that the hydrophilic GO-CNC composite functionalized PVDF microfiltration membrane exhibited higher wettability, lower protein and polysaccharides adsorption, and higher permeability compared to CNC/PVDF and previously reported GO/PVDF membranes. During long-term operation in MBR, the GO-CNC/PVDF membrane displayed superior antifouling performances with characteristic of less EPS accumulation, higher flux recovery ratio, lower irreversible fouling level and longer cleaning cycle, due to higher hydrophilicity and porosity as well as more negative zeta potential in comparison with the pristine PVDF and CNC/PVDF membranes. It can be expected that as a novel hydrophilic and antifouling additive, GO-CNC composite functionalized membranes would receive more extensive applications in MBR system for wastewater treatment and water reclamation.
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高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2018
·Vol. 94
·期 2
·398-408
·
IF 2.587
Chen Li,Lei Wang,Xudong Wang,Cuicui Li,Qibin Xu,Guangyuan Li
BACKGROUND Proton-exchange membrane (PEM) has a significant effect on the performance and overall cost of microbial fuel cells (MFCs). In this study, a novel composite PEM is fabricated by compositing sulfonated graphene oxide (SGO) with the Poly(vinylidene fluoride)-g-Poly(styrene sulfonic acid) (PVDF-g-PSSA) copolymer. The performance of MFCs with these newly prepared composite PEMs as separators was evaluated. A Quartz crystal microbalance with dissipation (QCM-D) combined with membrane-coated sensor crystals was used to investigate the biofouling mechanism of PEMs in MFCs at a micro-perspective. RESULTS The successful sulfonation of GO was confirmed by Fourier transform infrared spectrometry and X-ray photoelectron spectroscopy. When the SGO loading was 1.0 wt%, the SGO/PVDF-g-PSSA membrane had higher water uptake (32.56%), proton conductivity (0.083 S cm −1 ) and excellent hydrophilicity (contact angle 70.78°) than that of Nafion 117. QCM-D results further confirmed its better anti-fouling property vs that of the PVDF-g-PSSA, GO/PVDF-g-PSSA, and Nafion 117 membranes. Moreover, the MFC working with the SGO/PVDF-g-PSSA membrane exhibited the highest maximum power density and best stability of power production after 3 months of operation. CONCLUSION The SGO/PVDF-g-PSSA-1.0 composite PEM can be used as an alternative material to Nafion in MFCs and is conducive to the long-term stable operation of MFCs. © 2018 Society of Chemical Industry
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高影响因子
Journal of Materials Chemistry A
·
2018
·Vol. 6
·期 16
·7014-7020
·
IF 9.931
Jindan Wu,Yajie Ding,Jianqiang Wang,Tiantian Li,Haibo Lin,Jiping Wang,Fu Liu
To achieve highly efficient purification of emulsified oil, a superhydrophobic, superoleophilic and under-oil superhydrophobic poly(vinylidene fluoride) (PVDF) nanofibrous membrane was developed through a facile electrospinning strategy. The PVDF nanofibrous membrane exhibited a synchronous combination of nanofibers and micro/nanospheres, which was produced by solely controlling the PVDF concentration of the electrospun solutions. The fabricated PVDF nanofibrous membrane exhibited a water contact angle of 152° ± 2°, oil contact angle of 0° in air and under-oil–water contact angle of 152° ± 1° due to the inherently low surface energy and unique structures composed of nanofibers and micro/nanospheres. Thanks to the under-oil superhydrophobicity, hierarchical structure and high porosity (∼95%), the composite membrane showed extremely high permeability of 88 166 ± 652 L m−2 h−1 bar−1 with separation efficiency higher than 99%, which was few orders of magnitude higher than the previous findings. Moreover, the nanofibrous membrane exhibited robust continuous separation, indicating its scalable application for purifying emulsified oil.
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高影响因子
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