SEPARATION AND PURIFICATION TECHNOLOGY
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2021
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IF 7.312
Hengyang Mao,Shouyong Zhou,Shuo Shi,Ailian Xue,Meisheng Li,Jianjian Cai,Yijiang Zhao,Weihong Xing
Membrane technology can minimize spread of viruses in the environment during pandemics, however, its efficiency is highly limited by biofouling. In the current study, a composite membrane composed of commercial membrane material, poly(vinylidene fluoride) (PVDF), and thermo-responsive attapulgite (t-ATP) was developed. The t-ATP was synthesized by surface modification of attapulgite (ATP) nanofiber with poly( N -isopropylacrylamide) (PNIPAM). t-ATP acted as a nucleating seed to expedite crystallization of PVDF and as a hydrophilic modifier to enhance the wetting performance of membrane. The tensile strength, elongation, and permeance of membrane increased with increase in t-ATP content without compromising pore structure. PNIPAM chains in t-ATP were swollen or shrunken with the change in temperature, thus releasing adhesion between membrane and biofoulants. The modified membrane exhibited superior biofouling resistance performance compared with the pristine PVDF membrane owing to the hydrophilic property of t-ATP and the stretchable chains on its surface. Notably, 89% of biofouling on membrane surface was easily removed through a simple temperature-change coupling ultrasonic cleaning process. High performance of the PVDF/t-ATP membrane indicates its potential application for high-efficient biological wastewater treatment.
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高影响因子
CHEMOSPHERE
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2021
·
IF 7.086
Hailong Liu,Xiangjun Liao,Yuxia Ren
Amphiphilic copolymers containing hydrophilic and hydrophobic blocks represented by surfactants have proven to be more effective for modifying membranes than hydrophilic copolymers. However, studies on the effects of additive and coagulation bath pH on the morphology and properties of surfactant-modified membranes have rarely been reported. Hence, this study aims to investigate the effects of the additive dosage and the coagulation bath pH on the mechanisms of phase inversion and performance improvement of amphoteric fluorocarbon special surfactant (FS-50) blended PVDF membranes. It was observed that the pure water flux increased from 114.68 LMH/bar of the original membrane M0 to 205.02 LMH/bar of the blend membrane M1, and then to 615.88 LMH/bar of the coagulation-bath-regulated membrane MPH9 with a high BSA rejection rate of 90.86%, showing a two-stage jump. The addition of FS-50 promoted the instantaneous phase inversion of the membrane, allowing the blend membrane to exhibit a higher proportion of pore characteristics and stronger permeability. After that, the mechanisms of the membrane phase inversion process affected by the coagulation bath pH were interpreted according to the pH-response characteristics of FS-50 in terms of charge repulsion effect and compressed double-electron layer effect. Furthermore, the cross-sectional morphology and the surface structure of the membrane prepared in acidic and alkaline coagulation baths were significantly affected by the pH of the coagulation bath, exhibiting different features. For one, the porosity of the membranes gradually decreased as the acidity and alkalinity of the coagulation bath increased, and the membrane MPH9 exhibited both maximum surface and overall porosity. For another, the coagulation bath pH did not negatively affect the contact angle, surface roughness and tensile strength of the membranes. Overall, adjusting the dosage of FS-50 and the pH of the coagulation bath is a promising approach to greatly enhance membrane performance.
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PubMed
高影响因子
POLYMER DEGRADATION AND STABILITY
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2021
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IF 5.03
Yongqiang Guo,Chao Liu,Hongpeng Liu,Wenjing Wang,Hongbin Li,Chunhua Zhang
This study aims to explore the effects of gamma rays on various properties of poly(1,1-difluoroethylene) (PVDF) membranes under different irradiation conditions. The effects of 60 Co γ-ray irradiation on the hydrophilicity, permeability, and mechanical performances of the PVDF membranes were discussed. Results showed that the size of the radiation dose rate had almost no effect on the performance of the membranes, as determined by the total radiation dose. The fracture and collapse of the PVDF structure under anaerobic conditions were obviously lower than those under aerobic conditions. Advanced characterization methods confirmed that the initial impact of gamma rays on the PVDF membranes occurred between 50 and 200 kGy. When the total dose exceeded 200 kGy, structural collapse and chain scission caused by the oxidative degradation mechanism became widespread, thereby leading to the relaxation of the PVDF network and the decline in properties. This study provides valuable information for the application of PVDF membranes to radioactive wastewater and clarifies the mechanism of membrane irradiation degradation to help prolong the service life of membranes. In addition, low total irradiation dose can embellish polymers and thus provide a feasible method for modifying and grafting polymer membranes in the future.
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高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
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2021
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IF 7.664
Min Sang,Shuai Liu,Wenwen Li,Sheng Wang,Jun Li,Ji Li,Shouhu Xuan,Xinglong Gong
Recently, multifunctional materials have attracted tremendous attention in intelligent equipment and human–computer interaction, requiring the integration of electrical conductivity, sensing property and heating management. Herein, conductive MXene is formulated and deposited on the PVDF film surface and followed by integrating PI tape to construct a multifunctional PVDF/MXene/PI wearable electronic. The PVDF/MXene/PI with sandwich structure shows ideal mechanical strength and tensile toughness. Based on the conductive MXene network, PVDF/MXene/PI composite possesses excellent mechanosensation ability, which can sensitively monitor different human movements. Besides, PVDF/MXene/PI composite presents prominent Joule heating capability and achieves a temperature of over 80 ℃ at 6.5 V voltage. Insulated high-temperature resistant PVDF and PI tape as protective layers ensure the stability and safety of PVDF/MXene/PI heater. Moreover, PVDF/MXene/PI composite exhibits outstanding electromagnetic interference shielding effectiveness of 40 dB. Finally, PVDF/MXene/PI multifunctional electronic with fascinating multi-functions shows potential applications in human thermotherapy, human–machine interaction and electromagnetic wave protection.
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高影响因子
CARBOHYDRATE POLYMERS
·
2021
·
IF 9.381
Jingxuan Zhao,Hongxu Liu,Peng Xue,Song Tian,Shulin Sun,Xue Lv
An adsorptive membrane filtration based on polyvinylidene fluoride (PVDF) with chitosan (CS) and carboxylated carbon nanotubes (CNTs-COOH) is prepared by method of phase conversion, and the PVDF-CS@CNTs-COOH membranes can effectively separate anionic and cationic dye wastewater. Compared to pure PVDF membranes, PVDF-CS@CNTs-COOH increases pure water flux from 36.39 (L·m −2 ·h −1 ) to 85.25 (L·m −2 ·h −1 ), an increase of nearly 230%. The membrane exhibits excellent rejection performance in the filtration of six types of dye wastewater. The modified membranes also performed well in terms of rejection of mixed anionic and cationic dyes and also have a high performance in recycling, with a flux of over 94% for both anionic and cationic dyes. In addition, the adsorption curve fitting results showed that the adsorption process was more consistent with the pseudo-second-order adsorption kinetic model and Langmuir mode.
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PubMed
高影响因子
COMBUSTION AND FLAME
·
2021
·
IF 4.185
Jie Ji,Li Liang,Heng Xu,Guifeng Xiang,Haozhe Li,Pingyun Li,Xiang Zhou,Xiaode Guo
Nanothermites with fluoropolymer are popular among researchers due to their excellent combustion performance. Polyvinylidene fluoride (PVDF) is a kind of typical fluoropolymer with excellent chemical stability. This paper applied the evaporation method by employing the cyclohexane to realize the preparation of the core-shell structured Al@PVDF particles. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and fourier transform infrared spectroscopy were employed to characterize the core-shell structure and elemental distribution of the samples. Desirable corrosion resistance could be obtained at different surroundings of water, acid and alkali, indicating that Al@PVDF particles with the core-shell structured possess the improved stability than Al nanoparticles . Constant volume pressure tests were performed to characterize the energy release property. The results are applied to prove that the Al@PVDF particles have the outstanding pressure output ability in the environment short of oxygen. In terms of the ignition delay time, the light intensity and the combustion flame propagation, the combustion performance of samples were examined in air by the device with optical sensor and the high-speed camera to be compared with the samples by traditional physical mixing method. Al@PVDF particles have outstanding pressure output ability as well as more excellent combustion performance. In addition, the preparation method needs much lower technical requirements so that it is more suitable to apply to industrial production.
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高影响因子
DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 25
·8927-8937
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IF 4.39
Ying Liu,Na Wang,Zhongqiao Sun,Yide Han,Junli Xu,Yan Xu,Junbiao Wu,Hao Meng,Xia Zhang
MOF/polymer hybrid membranes integrate the surface activity of MOFs and the advantages of PVDF membranes, and can be used as adsorption membranes in the efficient removal of target organics. In this work, a new hybrid membrane of ZIF-67/PVDF with varying ZIF-67 dosages has been fabricated through a facile mechanical blending followed by a lyotropic phase transition. Methods including field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), FT-IR analyses and surface hydrophobicity/hydrophilicity measurements are applied to characterize the structure, physicochemical properties and membrane performances. Two synthetic triarylmethane dyes, cationic malachite green (MG) and anionic fuchsin acid (FA), are chosen as the main adsorption targets to evaluate the adsorption capacities of the resulting ZIF-67/PVDF hybrid membranes. Interestingly, all of the ZIF-67/PVDF hybrid membranes exhibit distinctly favorable efficiencies and selectivities toward MG and FA compared to pristine PVDF, which proves the positive roles of ZIF-67 in the adsorption ability of the hybrid membranes. The adsorption conditions are optimized and the adsorption kinetics and thermodynamics are analysed to study the adsorption mechanism. The reusability and the structural stability of the hybrid membranes undergoing cyclic adsorption processes are also discussed. To the best of our knowledge, this is the first time that good adsorption capacities for MG and FA for these MOF/PVDF membranes have been reported. This work highlights the prospective applications of MOF/PVDF hybrid membranes in the rapid and effective removal of target organics in the treatment of waste water.
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PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
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IF 5.774
Jiao Meng,Yan Xie,Yi-Hang Gu,Xi Yan,Yan Chen,Xiao-Jing Guo,Wan-Zhong Lang
Novel polyvinylidene fluoride-calcium alginate (PVDF-CaAlg) nanofiltration (NF) membranes were prepared by impregnating electrospun PVDF substrates with sodium alginate solution and crosslinking with CaCl 2 solution. The NF membranes were characterized via field emission scanning electron microscopy (FESEM) equipped with an energy-dispersive spectrometry (EDS), attenuated total reflectance Fourier transform infrared spectra (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). The results show that the prepared PVDF-CaAlg NF membranes exhibit dual thin-film-composite (TFC) structure and superior surface hydrophilicity. The highest pure water flux can achieve 63.8 L·m −2 ·h −1 ·bar −1 accompanied with a 98.5% rejection rate for methyl blue (MB), which is superior to many polymeric NF membranes. The prepared PVDF-CaAlg NF membranes exhibit much higher rejections for seven typical dyes, and the rejection slightly rises with the increase of impregnating time. In the long-term filtration process, the permeation flux for dye solution remains stable. PVDF-CaAlg NF membranes show good anti-fouling performance to BSA protein and lactobacillus.
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高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2021
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IF 8.742
Wei Zhang,Boyang Hu,Zhi Wang,Baoan Li
In recent years, omniphobic membranes have drawn much attention due to the strong repellence to various liquids. In this study, a PVDF composite membrane with omniphobic characteristics was prepared by constructing dual-scale hierarchical structure and introducing long chemical chains with the low surface energy. The special architecture was derived from the immobilization of TiO 2 @PDA@Cu composite nanoparticles on the surface via chemical bonding, and the fluorosilanization treatment with 1H,1H,2H,2H-perfluorodecyltriethoxysilane for membrane surfaces. A series of characterizations were implemented to explore composite nanoparticles’ morphology and composition, as well as membrane morphology and surface analysis. In addition, anti-fouling and anti-wetting behaviors of pristine and composite membranes were investigated by successive direct contact membrane distillation (DCMD) experiments, in which different contaminations containing inorganic salts, organic matter, surfactants and mineral oil were chosen as the feed. The results displayed that composite nanoparticles were obtained through the chelating effect of polydopamine (PDA) and the dual-scale structure was realized with the assistance of trimesoyl chloride (TMC). The omniphobic membrane exhibited strong repulsive forces to various liquids, such as water, SDBS solution (0.4 mM), CTAB solution (0.4 mM), tween-20 solution (0.4 mM) and mineral oil emulsion (0.2% v/v) with the contact angles of 168.0 ± 2.0°, 157.1 ± 1.5°, 160.0 ± 1.2°, 158.3 ± 1.5° and 152.5 ± 3.0°, respectively. Furthermore, compared to pristine membrane, the omniphobic membrane presented superior stability, higher salt rejection rate and excellent anti-wetting and anti-fouling performances in the DCMD tests. Thus, the composite membrane with superhydrophobic and superoleophobic features possessed great application potential for high salinity wastewater treatment in membrane distillation.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 137
·期 35
·49032
·
IF 2.52
Yupei Xian,Yonggang Shui,Meimei Li,Cunbao Pei,Qiyi Zhang,Yongyi Yao
Plenty of oily wastewater discharged from industrial and domestic sewage has deteriorated the environment severely, so stimuli-responsive membranes with switchable wettability have been of considerable attraction for its potential application in oil/water separation. In this work, a novel pH-dependent thermoresponsive membrane fabricated by grafting the poly[2-(diethylamino)ethyl acrylamide] (PDEAEAM) from the poly(vinylidene fluoride) (PVDF) membrane via surface-initiated atom transfer radical polymerization is explored to achieve the oil/water separation. The PDEAEAM- g -PVDF membrane shows hydrophilicity at room temperature under neutral condition while hydrophobicity at 50°C under alkaline condition. Wettability of the membrane at different temperatures is dominated by the lower critical solution temperature (LCST) of PDEAEAM, and the LCST of PDEAEAM is pH dependent. Due to the LCST of PDEAEAM, the membrane shows a variation of separation efficiency for separating hexadecane/water emulsion with temperature and pH. Typical separation efficiencies are 97.10% at 25°C under neutral condition and 30.26% at 50°C under alkaline condition.
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高影响因子
Functional Materials Letters
·
2020
·
IF 2
Zhong Yang,Jing Wang,Long He,Chaoyong Deng,Kongjun Zhu
Flexible dielectric capacitors are becoming shining stars in modern electronic devices. Ceramic particles with large dielectric constants and benign compatibility are attractive candidates to enhance the energy storage density of pristine polymer capacitors while guaranteeing their flexibility. In this work, double-shell structure of Al 2 O 3 (AO) and dopamine (PDA) were successively coated on the Nd-doped BaTiO 3 (NBT) particles and then introduced into the Poly(vinylidene fluoride) (PVDF) matrix. Obvious enhancement in dielectric constants was observed while the dielectric loss remained nearly constant. For the composite films with 1–4 vol.% NBT@AO@PDA NPs, the maximum energy density of 9.1 J/cm 3 and energy efficiency of 65% was achieved at 430 MV/m in the sample with 1 vol.% filling ratio, which are 1.4 and 1.3 times larger than those of pristine PVDF at 450 MV/m. The finite element simulation reveals the effective relief of the electric field concentration in the composite film induced by the AO and PDA layers. The greater improvement in the energy storage performance could be anticipated if the dispersity of NBT@AO@PDA NPs was further improved.
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SURFACE & COATINGS TECHNOLOGY
·
2020
·
IF 3.784
Jie Yang,Lulu Wang,Atian Xie,Xiaohui Dai,Yongsheng Yan,Jiangdong Dai
In this study, inspired by self-cleaning property of fish scale in water, a novel superhydrophilic and underwater superoleophobic tannin-metal complex@polyvinylidene fluoride (TA-Fe@PVDF) nanocomposite membrane was prepared by a facile and one-pot surface coating technology at room temperature using the ferric nitrate and tannic acid as the building blocks. The as-fabricated TA-Fe@PVDF nanocomposite membrane was characterized by scanning electron microscopy (SEM), attenuated total reflection fourier transform infrared spectroscopy (ATR-IR), atomic force microscope (AFM) and contact angle measuring instrument. It was found that the TA-Fe complexes improved the surface wetting, separation efficiency and repeatability. The optimal TA-Fe@PVDF-1 composite membrane was obtained at the concentration ratio of TA and Fe 3+ of 1:3, which show underwater oil contact angle of 155°, and low oil adhesion. The separation efficiencies of TA-Fe@PVDF-1 composite membrane for various oil-water mixtures and oil-in-water emulsions are higher than 99.5%. The membrane flux can reach 2551 L m −2 h −1 bar −1 for surfactant-stabilized petroleum ether-in-water emulsion separation, and 4505 L m −2 h −1 bar −1 for petroleum ether/water mixture. This nanocomposite membrane exhibits excellent repeatability and good chemical stability (salt/acid/alkali resistance), to be potentially applied for the treatment of oily wastewater.
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高影响因子
危险品化学品经营许可证（带存储）