SEPARATION AND PURIFICATION TECHNOLOGY
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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.
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高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2020
·Vol. 22
·期 23
·13143-13153
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IF 3.43
Pu Mao,Jiping Wang,Lixue Zhang,Qinzhao Sun,Xixia Liu,Liqiang He,Shujuan Liu,Siwen Zhang,Hao Gong
Polymer dielectrics with high dielectric performances and superior discharge energy capability are highly desirable for advanced electrostatic capacitor applications. However, the paradoxical relationship between dielectric polarization and electric breakdown behavior generally hinder their further enhancement in energy storage performances. Herein, polymer blended composite films with high energy storage capability were successfully fabricated by blending together poly(vinylidene fluoride) (PVDF) polymer and poly(vinylidene fluoride–trifluoroethylene–chlorofluoroethylene) (P(VDF–TrFE–CFE)) terpolymer. The P(VDF–TrFE–CFE) terpolymer has a high dielectric constant to provide a large electric displacement under an applied electric field far below its breakdown field, which is anticipated to modulate the dielectric polarization behavior of PVDF polymer when blended in different proportions. Consequently, the polymer blended composite film consisting of 20 wt% (P(VDF–TrFE–CFE)) terpolymer exhibits a high discharge energy density of 13.63 J cm−3 at an enhanced breakdown strength of 480 MV m−1. This obtained high discharge energy density is 84% higher than the pure PVDF film and 582% higher than a commercialized biaxially oriented polypropylene (BOPP). Large interfacial polarization and strong interaction of polymer chains between the PVDF polymer and P(VDF–TrFE–CFE) terpolymer may contribute to the tunable dielectric constant and electric breakdown strength, thus promoting the energy storage capability. This work establishes a facile, but effective approach to achieve the high energy storage capability of PVDF polymer-based flexible composite films for capacitive energy storage applications.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Di Liu,Jiulong Yin,Hai Tang,Hui Wang,Shasha Liu,Tingting Huang,Sisheng Fang,Kaixuan Zhu,Zongli Xie
Efficient separation and excellent antifouling performance of ultrafiltration (UF) membrane are highly desirable for sustainable wastewater treatment. This work reports a novel ZIF-67-imbedded PVDF (ZIF-67@PVDF) mixed-matrix UF membrane fabricated by nonsolvent-induced phase separation (NIPS) technique to reinforce efficient removal of dye wastewater via sulfate radical enhancement. The imbedded ZIF-67 well-dispersed within the membrane improved the membrane pore structure and benefited peroxymonosulfate (PMS) activation to generate sulfate radical that were confirmed by Electron spin resonance (ESR) spectroscopy. As a synergistic effect of pore structure and sulfate radical generation, the separation, antifouling and catalytic performance of the ZIF-67@PVDF membranes were greatly enhanced over a wide pH range. Even at a high pH of 11, the PMS on-line cleaning assisted ZIF-67@PVDF-1.0 membrane achieved high dye removal efficiency for orange Ⅱ (AO7, 97.3%), Methylene blue (98.2%), Rhodamine B (90.5%). The ZIF-67@PVDF membrane also showed good reusability and stability. This work demonstrates great potential of using self-cleaning UF membranes to treat dye wastewater.
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JOURNAL OF MEMBRANE SCIENCE
·
2019
·
IF 7.015
Weiming Yu,Ying Liu,Yanchao Xu,Renjie Li,Jianrong Chen,Bao-Qiang Liao,Liguo Shen,Hongjun Lin
Ultrafiltration (UF) membrane has recently drawn interest in textile and dyeing wastewater treatment due to its unique advantages of low-cost and large flux. However, its low rejection to dyes and developing appropriate membrane materials remain the major hurdles for its large-scale application. Herein, we developed a novel conductive polyvinylidene fluoride (PVDF)-Ni membrane combined with an external electric field to treat typical dyes. The membrane could be fabricated by a facile and low-cost method. The conductive PVDF-Ni membrane showed favorable rejection rate of Congo red (CR) (100%) and extremely high permeance (137.5 ± 6.8 L m −2 h −1 bar −1 ). To our knowledge, the permeance has exceeded the maximal literature record for the membranes with similar rejection rates of CR. The novel membrane combined with external electric field also provided a unique aeration mode: in-situ aeration, due to its good electrocatalytic activity for hydrogen evolution reaction (HER) (overpotential of 157 mV at the current density of 10 mA cm −2 ). Benefit from the in-situ aeration, the PVDF-Ni membrane showed 94% flux recovery after filtration of bovine serum albumin (BSA). Additionally, the PVDF-Ni membrane exhibited evident resistance to dye absorption and antibacterial activity. These versatile proprieties, together with the facile fabrication process, indicated the tremendous application prospect of the fabricated PVDF-Ni membrane for textile and dyeing wastewater treatment .
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JOURNAL OF HAZARDOUS MATERIALS
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2019
·
IF 7.65
Liang Zhou,Yi He,Heng Shi,Guoqing Xiao,Shunhui Wang,Zhenyu Li,Jingyu Chen
Water-purification membranes with high water flux, excellent recycling ability, good anti-fouling property, wide range for different oil/water emulsions separation, and strong water-soluble dyes removal ability are highly desirable for water purification but still a challenge to be realized. In this work, we show a simple method to address this challenge, in which halloysite nanotubes (HNTs) have been decorated on the poly (vinylidene fluoride) (PVDF) membrane surface through one-pot method via the aid of KH550 and dopamine. The [email protected] composite membrane exhibits superhydrophilic and under-water superoleophobic performance. In addition, our membrane can separate wide oil/water emulsions (including surfactant-stabilized and surfactant-free emulsions) from wastewater with high efficiency (>99.65%), outstanding recycle ability with good flux recovery rate (FRR > 95%) and good anti-fouling performance (the underwater oil contact angle (OCA) is 155.8 ± 1.8° with low oil adhesion) and high water flux (7994 ± 150 L m −2 h -1 ). Interestingly, our membrane also removes different water-soluble dyes (e.g., Congo red, methylene blue, and rhodamine B) from waste water by simply filtering. Those outstanding properties make our membrane hold great potential applications in real-world water purification and environmental protection.
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JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
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2018
·
IF 2.891
Bo Gao,Weiping Chen,Jiadong Liu,Jiajun An,Lei Wang,Ying Zhu,Mika Sillanpää
Based on the concept of dynamic membrane and photocatalytic membrane reactor (PMR), the dynamic photocatalytic membrane reactor is developed via deposition of ZnIn 2 S 4 suspension on polyvinylidene fluoride (PVDF) membrane. Operating with effluent circulating to the photocatalytic membrane reactor, the highest total organic carbon (TOC) removal efficiency of 57% is obtained after 3 h reaction with 1.88 mg cm −2 photocatalyst under the flux of 84.06 L m −2 h −1 and light intensity of 50 mW cm −2 . Operating with continuous influent and effluent mode under the flux of 26.09 L m −2 h −1 and light intensity of 50 mW cm −2 , an average of 50% removal efficiency can be maintained during the 24 h photocatalytic reaction with photocatalyst loading of 1.88 mg cm −2 when the initial concentration of tetracycline is 10 mg L −1 . Under the same operating conditions, more than 92% removal efficiency can be maintained during 36 h photocatalytic reaction when lower initial concentration of 100 μg L −1 is applied. After this reaction, the characterizations show that the surface and structure of PVDF basement membrane are not affected.
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DESALINATION
·
2015
·
IF 3.756
Lei Wang,Danxi Huang,Xudong Wang,Xiaorong Meng,Yongtao Lv,Xin Wang,Rui Miao
To obtain a high-performance polyvinylidene fluoride (PVDF) membrane, low-temperature thermally induced phase separation (LT-TIPS) was employed to prepare microporous flat PVDF membranes and hollow-fiber membranes using diluent mixtures of triethylphosphate and diethylene glycol monoethyl ether acetate. The membrane morphology was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results show that thermally induced phase separation (TIPS) played a more important role than nonsolvent-induced phase separation (NIPS) in determining the cross-sectional morphology of the membranes, and the surface structure was mainly affected by NIPS in a low-temperature (0 °C) coagulation bath . By increasing the temperature of the coagulation bath, different structures of membranes, such as spherulites and cellular and sponge structures, were observed. It is believed that the formation mechanism of these membranes depended on a combined NIPS and TIPS process. Wide-angle X-ray diffraction (XRD) analysis indicated that PVDF crystallized into an α-phase crystal structure for all the membranes tested. In addition, the porosity, tensile strength and filtration performance of the flat membranes were measured. On the basis of the above results, a hollow fiber membrane with highly interconnected pores and high porosity could be prepared employing LT-TIPS.
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COMPOSITES SCIENCE AND TECHNOLOGY
·
2014
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IF 3.633
Huyan Shi,Fu Liu,Lixin Xue,Huafeng Lu,Qingbo Zhou
Ag-loaded zeolites were synthesized and embedded into the outer layer of poly(vinylidene fluoride) (PVDF) dual-layer hollow fiber membrane (D) using a dry-jet wet-spinning co-extruding technique. The distribution of the Ag-loaded zeolites in the outer layer was confirmed by field emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDX). It was found that the D contained only 54% of the amount of Ag-loaded zeolites that were distributed throughout the cross section of PVDF single-layer hollow fiber membrane (S), as calculated by thermogravimetric analysis (TGA). However, D showed excellent antibacterial efficiency and resistance to bacterial adhesion because of the higher concentration of Ag + in the outer layer of the membrane. The surface morphologies , pure water flux, mean pore size, pore size distribution , and thermal stability of both PVDF membranes were also investigated.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2015
·Vol. 133
·期 9
·
IF 1.768
Tongbing Li,Dekun Sheng,Zhengrong Xiong,Xiumei Gao,Fance Ji,Yuming Yang
There is a contradiction in making completely opaque and white plastic film with a required high TiO 2 filling fraction, which resulted in inefficient pigment utilization and high cost. Two methods were used here to overcome the contradiction. Firstly, TiO 2 was grafted with poly(methyl methacrylate) (PMMA) by atom transfer radical polymerization to improve the pigment dispersion in poly(vinylidene) fluoride (PVDF). Secondly, minute amounts of carbon black (CB) were added into the PMMA- g -TiO 2 /PVDF system to enhance opacity and decrease TiO 2 fraction. The structure, morphology, and properties of PMMA- g -TiO 2 hybrid particles and composite films were investigated by FTIR, TEM, TGA, SEM, DMA, covering power meter, and UV/VIS spectrophotometer, etc. It was observed that PMMA- g -TiO 2 was dispersed uniformly as individual particles in PVDF due to the good compatibility between PMMA and PVDF. Therefore, the opacity of PMMA- g -TiO 2 /PVDF films was markedly higher than unmodified-TiO 2 /PVDF ones. Adding minute amounts of CB can significantly increase the opacity of the thin film due to its absorption effect on decreasing light transmittance. The contrast ratio (CR) of the PMMA- g -TiO 2 /PVDF film with 20 μm thickness and 25 vol % TiO 2 was 97.67%, lower than the critical CR 98% for a complete opacity, however, the CR of sample with 10 vol % TiO 2 was 98.1% as the CB concentration was 2 × 10 −4 g/cm 3 , saved more than 15% TiO 2 . We proposed that a critical thickness d 0 existed for the CB/PMMA- g -TiO 2 /PVDF composite films, under which the light reflectance increased as a function of thickness, otherwise, the reflectance kept constant. Besides, d 0 could be decreased by increasing CB concentration. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43064.
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RSC Advances
·
2016
·Vol. 6
·期 25
·20542-20550
·
IF 3.289
Renjie Li,Lifen Liu,Yuehua Zhang,Fenglin Yang
In this paper, nanoscale MnO2 particles were attached onto the surface of a PVDF flat sheet membrane, step by step, first through dispersion of graphene oxide (GO) in the PVDF membrane, then reduction of immobilized GO by hydroiodic acid and further micro-wave assisted oxidation of RGO (reduced graphene oxide) by KMnO4 and formation of MnO2 on GO. The SEM observation revealed an asymmetric structure with a finger-like transition layer dominating the membrane of PVDF/MnO2. The uniform distribution of MnO2 on the membrane is revealed by EDX and XPS analysis. The attached MnO2 endowed the membrane with high adsorption capacity for aqueous Ni(II). The adsorption was spontaneous and endothermic, fitting a pseudo-first-order kinetic model and Freundlich isotherm model well. The pure water flux and stable permeation flux of the PVDF/MnO2 membrane reached 31.2 L m−2 h−1 and 9.0 L m−2 h−1 under 0.1 MPa, which were 2.3 and 2.6 times those of the PVDF membrane. The analysis of the fouling resistance and flux recovery ratio indicated that the PVDF/MnO2 membrane had better antifouling properties than the PVDF membrane, attributed to the changes of membrane morphologies and surface hydrophilicity. The PVDF/MnO2 membrane had a high removal ratio (≥87.4%) of Ni2+ in dynamic adsorption. Meanwhile the Ni(II) adsorbed membrane could be easily regenerated by a 0.1 M HNO3 solution.
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APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Bao-Xu Jiang,Shuang-Bao Li,Ting-Ting Xu,Jian Li,Yu-Teng Zhang
Adsorption membranes have become a hot spot for wastewater treatment in recent years. Due to the lack of active sites in traditional inert materials such as polyvinylidene fluoride (PVDF) membranes, it is difficult to bind pollutants in water with high affinity. Therefore, in this study, ZrT-1-NH 2 /PVDF mixed matrix membranes (MMMs) were prepared by combining an amino-functionalized Zr-based metal–organic cage (ZrT-1-NH 2 ) with a polymer substrate via non-solvent-induced phase separation method for the efficient removal of Orange G (OG) from water. This method has many advantages such as simplicity in operation, high applicability, controllable MOFs loading. The structural characteristics and adsorption properties and of MMMs were also investigated through a series of characterizations and experiments. The result shows that in a 100 mL OG solution with an initial concentration of 50 mg/L and pH=3, M60 exhibited significant adsorption capacity, the removal efficiency reached 97.23 %, with an adsorption capacity of 64.18 mg/g, which is much higher than the pristine PVDF membrane. It is mainly attributed to electrostatic interactions and hydrogen bonding interactions between ZrT-1-NH 2 and OG molecules. This is consistent with the DFT calculations. The introduction of ZrT-1-NH 2 filler improves the performance of PVDF membranes and expands their potential applications.
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LANGMUIR
·
2025
·
IF 3.9
Yiming Wu,Jing Yang,Ruifeng Zhang,Hongji Li,Ruihua Mu,Yamei Zhao
Polyvinylidene fluoride (PVDF) membranes represent a potential technology for the in-depth treatment of organic dye-containing wastewater. Nevertheless, the intractable membrane fouling and the limited versatility have significantly constrained its applications. Herein, through the nonsolvent-induced phase inversion method, we have successfully fabricated the PDA@MgO/PVDF and PDA@ZnO/PVDF membranes, which are modified by the synergistic action of MgO or ZnO nanoparticles with polydopamine (PDA), respectively. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), as well as the analyses of pore structure, contact angle, and surface free energy, were utilized to characterize the hybrid membranes. The results demonstrate that the modification of PDA@MgO and PDA@ZnO can enhance the hydrophilicity, pure flux, dye rejection, and pollution resistance of PVDF membranes. The enhanced hydrophilicity of the modified membranes results from the increase in surface free energy and its polar component term. Comparatively, the PDA@ZnO/PVDF membrane exhibits a smaller contact angle (69°) and a higher pure water flux (378.63 L/m2·h·bar), whereas the PDA@MgO/PVDF membrane possesses greater mechanical strength and better antifouling performance. The PDA@MgO/PVDF membrane can achieve a rejection rate of 94.6% for disperse deep blue 79, and the flux recovery rate can reach approximately 82%. This research offers novel insights into the application of PVDF membranes for the treatment of organic dye-containing wastewater.
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