INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2024
·
IF 3.8
Jiong Li,Guoyong Du,Chunping Deng,Huatao Zhang,Lijuan Dai
In recent years, modified membranes for oil–water separation have garnered significant attention. However, the complexity of the process, low efficiency, and serious oil contamination have been the main obstacles to its application. Hence, there is an urgent need to explore simple, environmentally friendly modification methods. Inspired by adhesive bioproteins and diatomaceous silica, this study presents a simple, low-cost, and environmentally friendly biomimetic coating strategy to prepare a highly efficient oil–water separation membrane with convenient separation and excellent resistance to oil fouling. Using pyrogallic acid (PG) and silane coupling agent KH550, a one-step modification of the poly(vinylidene fluoride) (PVDF) microfiltration membrane (MF) was conducted, transitioning the surface wettability of the PVDF membrane from highly hydrophobic to superhydrophilic. This resulted in layered nanoscale papillary structures on the PVDF–MF surface, imparting superhydrophilicity and underwater superoleophobicity, along with excellent oil–water separation capability. Under a transmembrane pressure of 0.85 bar, systematic testing of the modified membrane demonstrated that the stable flux of the emulsion is approximately 950 L m–2 h–1, with an oil rejection rate exceeding 99% and significantly improved fouling resistance, as well as excellent chemical stability and salt resistance. The “green” in situ biomimetic silicification strategy is equally applicable to inert materials such as polytetrafluoroethylene (PTFE) membranes, demonstrating its significant potential for application on other materials.
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高影响因子
RSC Advances
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2016
·Vol. 6
·期 67
·62186-62192
·
IF 3.289
Jianjian Cai,Shouyong Zhou,Yijiang Zhao,Ailian Xue,Yan Zhang,Meisheng Li,Weihong Xing
The hydrophilicity of a thermo-responsive PVDF/palygorskite-g-PNIPAAM hybrid ultrafiltration membrane was enhanced via surface segregation induced by coagulation bath temperature (CBT). The N1s content of the hybrid ultrafiltration membranes prepared at 5 and 20 °C is 1.77% and 1.02%, respectively while that of the membrane prepared at 40 °C is just 0.73%. This indicated that the PNIPAAM chains could be dragged to the membrane surfaces or pores via surface segregation induced by temperature. This resulted in higher hydrophilicity and permeability as well as thermo-responsiveness for membranes prepared at lower temperatures. The initial water contact angle of the PVDF/palygorskite-g-PNIPAAM hybrid ultrafiltration membrane prepared at 5 and 20 °C is 75.2° and 75°, respectively, which is about 6° lower than the one prepared at 40 °C. A higher pure water flux (PWF) of about 366 L m−2 h−1 at 40 °C was obtained for the hybrid membrane prepared at 5 °C while the one prepared at 40 °C only reached 274 L m−2 h−1. Meanwhile, membranes prepared at low temperature exhibited fewer macrovoids, lower membrane thickness and larger elongation.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2017
·Vol. 28
·期 18
·13360-13370
·
IF 2.019
Lu Haowei,Lin Jiaqi,Yang Wenlong,Liu Lizhu
The Ba 0.859 Ca 0.141 Zr 0.106 Ti 0.894 (BCZT) nano-particles were modified by polyimide (PI) through a chemical coating method. And the PI@BCZT/polyvinylidene fluoride (PVDF) flexible composite films were fabricated by solution casting method. The transmission electron microscopy and scanning electron microscopy results show that the nano-particles is about 50 nm, PI is uniformly coated on the surface of BCZT nano-particles about 7–10 nm as well as there are uniform and improved dispersion in the matrix after modification. A series of dielectric properties were carried out. The results show the 50 vol% composites own a remarkably enhanced dielectric permittivity (ε r = 130) at 100 Hz. After modification, the breakdown strength has increased from 20 to 96 kV mm −1 and the loss tangent is reduced from 1.8 to 0.2 at 100 Hz compare with un-modified composites in 40 vol% dopant. With the increase of dopant, ferroelectricity of composites can be enhanced. The optimal residual polarization is 40 vol% PI@BCZT composites, which possess 1.025 μC/cm 2 under 50 kV/mm external electric field. In addition, after modification, thermo-gravimetric analysis exhibits the degradation temperature Td 5% and Td 10% of PI@BCZT/PVDF composites can be enhanced about 5–10 °C and show better thermal stability than un-modified composites.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2024
·
IF 8.1
Guijing Chen,Songzhe Li,Xifan Li,Xin Li,Baicang Liu
The collection and reuse of roof rainwater can alleviate water shortage for daily life. In this study, polyvinylidene fluoride hollow fiber membranes tuned with three multi-walled carbon nanotubes (pure MWCNTs, MWCNTs-COOH, and MWCNTs-OH) were prepared using a non-solvent induced phase separation method for gravity-driven membrane filtration to purify roof rainwater. The results showed that the MWCNTs were distributed on the membrane surface and throughout the porous structure of the cross-section, which changed the pore structure parameters and hydrophilicity. The pure water flux of the MWCNTs tuned membranes increased by 152.5 % at 1.0 bar, and the rejection rates of humic acid and bovine serum albumin increased from 97.4 % and 75.7 % to 98.9 % and 96.3 %, respectively. The extended Derjaguin, Landau, Verwey, and Overbeek (xDLVO) theory states that the presence of MWCNTs leads to changes in the physicochemical properties of the membrane surface, resulting in membranes with different anti-fouling behaviors. A gravity-driven membrane filtration test was continuously operated for 100 days, and all membranes removed 25.0–26.7 %, 49.5–53.0 %, and 89.0–93.3 % of total dissolved solids, dissolved organic carbon, and turbidity from roof rainwater, respectively. However, the pure MWCNTs modified membrane with relatively hydrophobic properties showed a 12.4 % increase in flux over the unmodified membrane. Importantly, the presence of the MWCNTs in the membrane changed the microbial diversity in the biofilter cake layer.
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ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Mengmeng Chen,Neng Hu,Weijia Wang,Lin Lei,Huiqing Fan,Peter Müller-Buschbaum,Qi Zhong
Inspired from seaweed swayed by waves, the enhanced hydrogen evolution is realized in porous and hybrid g-C 3 N 4 /Pt-PVDF electrospun membranes via piezoelectricity from water flow energy. The membranes are fabricated by dispersing g-C 3 N 4 /Pt into the mixed solution of PVDF and PEO, followed by electrospinning and selective removal of PEO. By changing the PEO amount, the pore size in nanofibers is adjusted. Due to the hydrogen bonding between g-C 3 N 4 /Pt and PVDF, the β phase of PVDF is increased, beneficial for the piezoelectricity performance. When the electrospun membranes are exposed to water flow, an additional potential field is triggered due to the deformation of PVDF. It not only eases the photogeneration of charge carriers from g-C 3 N 4 /Pt but also hinders their recombination. The prolonged lifetime significantly improves the photocatalytic water splitting of g-C 3 N 4 /Pt under visible light. The hydrogen evolution in the electrospun membranes (PVDF to PEO = 4:1) is profoundly improved to 9 278 µmol h −1 g −1 , almost doubled to the pure g-C 3 N 4 /Pt nanosheets (5 220 µmol h −1 g −1 ). Therefore, the seaweed-inspired electrospun membrane is a promising strategy for the efficiently photocatalytic water splitting via g-C 3 N 4 in an aqueous environment, such as a natural sea and lake, by the piezoelectricity gained from the water flow energy.
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Polymers
·
2024
·Vol. 16
·期 13
·1781
·
IF 4.7
Arsalan Ahmed,Nazakat Ali Khoso,Muhammad Fahad Arain,Imran Ahmad Khan,Kashif Javed,Asfandyar Khan,Sanam Irum Memon,Qinguo Fan,Jianzhong Shao
The demand for self-powered, flexible, and wearable electronic devices has been increasing in recent years for physiological and biomedical applications in real-time detection due to their higher flexibility and stretchability. This work fabricated a highly sensitive, self-powered wearable microdevice with Poly-Vinylidene Fluoride-Tetra Fluoroethylene (PVDF-TrFE) nano-fibers using an electrospinning technique. The dielectric response of the polymer was improved by incorporating the reduced-graphene-oxide (rGO) multi-walled carbon nano-tubes (MWCNTs) through doping. The dielectric behavior and piezoelectric effect were improved through the stretching and orientation of polymeric chains. The outermost layer was attained by chemical vapor deposition (CVD) of conductive polymer poly (3,4-ethylenedioxythiophene) to enhance the electrical conductivity and sensitivity. The hetero-structured nano-composite comprises PVDF-TrFE doped with rGO-MWCNTs over poly (3,4-ethylenedioxythiophene) (PEDOT), forming continuous self-assembly. The piezoelectric pressure sensor is capable of detecting human physiological vital signs. The pressure sensor exhibits a high-pressure sensitivity of 19.09 kPa−1, over a sensing range of 1.0 Pa to 25 kPa, and excellent cycling stability of 10,000 cycles. The study reveals that the piezoelectric pressure sensor has superior sensing performance and is capable of monitoring human vital signs, including heartbeat and wrist pulse, masticatory movement, voice recognition, and eye blinking signals. The research work demonstrates that the device could potentially eliminate metallic sensors and be used for early disease diagnosis in biomedical and personal healthcare applications.
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PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2024
·
IF 8.4
Qichao Ding,Kedi Dong,Xinyu Si,Tonghu Xiao,Xing Yang
Amphiphobic membranes have attracted much attention in membrane distillation (MD) applications, due to its potential in simultaneously resisting membrane wetting and fouling when treating complex wastewater. The current amphiphobic membranes often require non-trivial design of multilevel re-entrant structure. Here we proposed a new class of amphiphobic membranes without multilevel re-entrant surface, by creating a composite poly(vinylidene fluoride)/polyvinyl alcohol/SiO 2 membrane with asymmetric structure and well-controlled small surface pores via the NTIPS method, followed by direct fluorination via chemically binding the –OH of polyvinyl alcohol and low surface energy moieties 1H,1H,2H,2H-perfluorodecyl-triethoxysilane, assisted by 3-aminopropyltriethoxysilane and trimesoyl chloride. The amphiphobic membrane showed superior liquid entry pressure above 5 bar with various simulated saline feeds containing surfactants and organic pollutants. The amphiphobic membrane demonstrated robust anti-wetting and anti-fouling performance through a series of 24-h direct contact MD experiments using the above feeds, presenting stable water flux and high rejection, e.g., flux of 50.6 kg/(m 2 ·h) and rejection >99.9 % with feed containing 3.5 wt% NaCl, 1 mM FA, and 2 mM SDS. The results demonstrated the fabrication of robust amphiphobic membrane through simple procedure utilizing the synergy between pore structure and surface chemistry, inspiring more efforts to design adequate membranes for treating complex wastewater.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Weizhi Liu,Yongqiang Guo,Zhiwei Xue,Hao Sun,Xiaofeng Lin,Chao Liu
Polyvinylidene fluoride (PVDF) membrane is a cheap and commonly used separation material, but its inherent hydrophobicity results in significant membrane contamination, which limits its engineering application and further development. The hydrophilic PVDF-g/co-NVP membrane was prepared through low-dose γ-ray irradiation and using N-vinyl-2-pyrrolidinone (NVP) as a modifier in this study. The effects of γ-ray dose and incorporating NVP additive on the microstructure, hydrophilicity, anti-fouling capability, and mechanical capacity of membranes were discussed. Molecular dynamics (MD) simulation method was used to comprehensively investigate the impact of the NVP on the physicochemical characteristics of membrane structure. Under a specific NVP load, the water contact angle of the membrane decreases from 87.92° to 52.66°. The pure water permeance reaches 362.1 L/m 2 h, and the porosity increases to 55.21 %±1.29 %, which indicates that γ-ray irradiation with NVP addition can effectively adjust the pore structure and hydrophilicity of the membrane. During anti-fouling test against bovine serum albumin (BSA), the modified membrane exhibits remarkable anti-fouling characteristics, including reduced BSA accumulation, enhanced flux recovery, lower irreversible contamination level, and extended cleaning cycle compared with the original pure PVDF membrane because of its higher hydrophilicity and positive zeta-potential value. This study elucidates the mechanism underlying γ-ray graft modification of PVDF membranes, thereby providing valuable insights into the development of efficient functional membrane materials.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2024
·
IF 8.1
Meng Wei,Pengfei Zhai,Yihan Li,Xin Zhao,Jiancheng Li,Tao Zhang,Guanghui Liu,Zhanjun Yu,Song Xu
The NASICON-type ceramic Li 1·5 Al 0.5 Ge 1.5 (PO4) 3 (LAGP) electrolyte has been proposed as the most competitive candidates of electrolyte materials toward solid-state Li metal batteries (LMBs) by reason of its high ionic conductivity , cyclic stability under extreme temperatures and wide voltage window. However, poor interface contact, high interfacial resistance and intractable mechanical properties greatly limit its practical applications. In this work, an inorganic-polymer “LAGP in PVDF” quasi-solid-state electrolyte (QSSE) is developed via solution casting method, in which pyr14TFSI ionic liquid (IL) and LiTFSI are combined as functional wetting interface . Benefiting from the coherent interaction of LAGP nanoparticles incorporated into the polymer matrix , and inherent protection of IL, the overall performance of the optimized QSSE include thermal stability, dense structure, flexibility and electrochemical properties . The XRD, SEM, XPS tests demonstrate that the IL using as a solid/electrolyte modified interlayer can enhance Li + transport, interfacial infiltration and homogenize lithium deposition. The LiFePO 4 |PL-25LAGP|Li solid-state battery presents an excellent circulation performance under ambient temperature, which displayed an initial discharge specific capacity of 146.8 mAh g −1 at 0.5C and capacity retention of 96.25 % after 150 cycles. The flexibility PL-LAGP CSE shows superior safety and greater development potential for the “LAGP in PVDF” composite electrolyte in solid state LMBs.
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高影响因子
Journal of Water Process Engineering
·
2024
·
IF 6.3
Lei Cao,Hongpeng Liu,Haoyu Li,Huiming Lin,Lingfei Li
Microfiltration membrane separation technology has been widely employed in the field of oil-water separation because of its low energy consumption. However, the practical applications of polyvinylidene fluoride (PVDF) microfiltration membrane are limited due to its strong hydrophobicity and poor anti-fouling. A superhydrophilic/underwater superoleophobic PVDF microfiltration membrane is prepared through surface co-coating inspired by mussel chemistry. The dopamine (DA) and fulvic acid (FA) generate a hydrophilic coating with hydrophilic functional groups through a mild Michael addition/Schiff base reaction. When the DA/FA ratio is 2/8 and a modification time is 6 h, the pure water flux reaches 8011 L m −2 h −1 bar −1 , the flux of oil-in-water emulsion is 1915 L m −2 h −1 bar −1 , and the rejection is 99.1 %. The retention rate of the membrane for oil-water emulsions containing different oil phases (heavy and light oils) is consistently above 98.5 % and shows high recoveries ( FRR > 86.6 %) after twenty separations. Modified membranes have high anti-pollution ability for characteristic pollutants in water bodies (for example: BSA, SDS). This work demonstrates a simple surface coating preparation method that has excellent separation performance, and environmental friendliness, offering a promising strategy for large-scale modified membranes to treat oily wastewater.
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高影响因子
POLYMER COMPOSITES
·
2024
·
IF 4.8
Weiji Li,Xinrui Yan,Lu Ye,Changning Ran,Yue Zhang,Ruiqi He,Bixuan Zhu,Yu He,Jiacheng Guo,Hongwei Li,Jianjun Zhang,Sude Ma
In this paper, the carboxylic acid modifier 2,3,4,5-tetrafluorobenzoic acid (F4C) was used to modify the BaTiO 3 (BT) nanoparticles, which acted as a coupling agent. The modified BT(F4CBT) nanoparticles, polyvinylidene fluoride (PVDF), and polymethylmethacrylate (PMMA) were used to make the modified nanocomposite films: PVDF/PMMA-F4C-BaTiO 3 nanocomposite films. The unmodified BT nanoparticles were used to make the unmodified nanocomposite films: PVDF/PMMA-BaTiO 3 nanocomposite films. The modification effect of the F4C resulted in an increase in the amount of β-phase and γ-phase, a decrease in the amount of α-phase, and a decrease in the overall crystallinity of the PVDF-based nanocomposite films. The dielectric constant of the PVDF/PMMA-F4C-BaTiO 3 nanocomposite films reached a maximum value of 16.7 at a frequency of 100 Hz at 4 wt% F4C, which was 40.3% higher than that of the unmodified PVDF/PMMA-BaTiO 3 films. The F4C content of 2 wt% PVDF/PMMA-F4C-BaTiO 3 nanocomposite films showed the lowest dielectric loss of 0.055, which was 56.7% lower than the unmodified PVDF/PMMA-BaTiO 3 films. The breakdown strength of the PVDF/PMMA-F4C-BaTiO 3 nanocomposite films increased and then decreased with the increase of the F4C content, and the highest breakdown strength was 2800 kV/cm at 4 wt% F4C, which was 55.6% higher than the unmodified PVDF/PMMA-BaTiO 3 films. The charging density of the PVDF/PMMA-F4C-BaTiO 3 nanocomposite films reached a maximum value of 20.65 J/cm 3 at 4 wt% F4C content, which was 394% higher than the unmodified PVDF/PMMA-BaTiO 3 films. Highlights Modification of ceramic nanoparticles with carboxylic acid coupling agent. The dielectric properties of the modified nanocomposite film were significantly improved. Maximum polarization and charge/discharge density were greatly improved by coupling agent modification.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 28
·e55626
·
IF 2.7
Xiao Li,ChongXiao Yuan,Guoqi Gao,Hengqing Zhou,Nannan Zhang,Xinyue Yang,Xiaofang Liu,Huajun Sun
The demand for self-powered sensing technology and energy harvesting system necessitates high-performance and flexible piezoelectric materials. This paper presents a novel approach utilizing coaxial electrospinning to fabricate all-organic PVDF/PMMA piezoelectric fiber films with a shell–core structure. The resulting fiber films, cut into 2 × 2 cm 2 square pieces and hot-pressed every three pieces, demonstrate enhanced piezoelectric properties while retaining high flexibility. The interaction between the CO bonds in the PMMA polymer and the CH 2 in PVDF promotes the arrangement of F atoms in PVDF, enhancing the content of the piezoelectric active phase. Additionally, the coaxial electrospinning process fosters vertically oriented hydrogen bonds between PVDF and PMMA, augmenting cross-linking and improving mechanical properties. Notably, when the PVDF to PMMA layer volume ratio is 5:1, the piezoelectric coefficient (| d 33 |) of the composite fiber film exhibits a significant 60% increase from 10 pC N −1 in neat PVDF to 16 pC N −1 . This research holds substantial promise for applications in self-powered sensing and energy harvesting piezoelectric materials.
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