PHYSICS OF FLUIDS
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2023
·Vol. 35
·期 3
·
IF 4.6
Rong Feng,He Limin,Lǚ Yuling,Lu Xiaolei
To investigate the force model and motion law of oil droplets in water near the wetted wall, oil droplets with R 1 = 0.29–0.62 mm and oil films with R 2 = 1–6 mm are solved numerically. In addition to buoyancy, flow resistance, and added mass force, the film-induced force triggered by the wetted wall constraint is also introduced into the force model. The drainage process is described using the Stokes–Reynolds equation, and the Young–Laplace equation is used to calculate the pressure within the water film. The results show that the force model can be coupled with the Stokes–Reynolds–Young–Laplace model equation to better describe the drainage dynamics near the wetted wall. The pressure distribution law is closely related to the shape of the water film, especially when the oil–water interface is in the shape of a dimple, which can lead to the formation of negative pressure zones within the water film. The maximum pressure first grows in an exponential, then logarithmic pattern and eventually approaches the equivalent Laplace pressure. Around the critical size, the direction of the film-induced force changes and the form of action switches between driving and drag forces. The film-induced force's dominant effect is strongest when the curvature radius of the oil film is comparable to the droplet size.
研究领域:
流体力学
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界面化学
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DOI
高影响因子
Membranes
·
2022
·Vol. 12
·期 1
·65
·
IF 4.562
Jun Pan,Kun Chen,Zhaoliang Cui,Omar Bamaga,Mohammed Albeirutty,Abdulmohsen Omar Alsaiari,Francesca Macedonio,Enrico Drioli
Due to the good hydrophobicity and chemical resistance of poly(ethylene trifluoroethylene) (ECTFE), it has been an attractive potential material for microfiltration, membrane distillation and more. However, few porous hydrophobic ECTFE membranes were prepared by thermally induced phase separation (TIPS) for membrane condenser applications. In this work, the diluent, di-n-octyl phthalate (DnOP), was selected to prepare the dope solutions. The calculated Hassen solubility parameter indicated that ECTFE has good compatibility with DnOP. The corresponding thermodynamic phase diagram was established, and it has been mutually verified with the bi-continuous structure observed in the SEM images. At 30 wt% ECTFE, the surface contact angle and liquid entry pressure reach their maximum values of 139.5° and 0.71 MPa, respectively. In addition, some other basic membrane properties, such as pore size, porosity, and mechanical properties, were determined. Finally, the prepared ECTFE membranes were tested using a homemade membrane condenser setup. When the polymer content is 30 wt%, the corresponding results are better; the water recovery and condensed water yield is 17.6% and 1.86 kg m−2h−1, respectively.Keywords:membrane condenser;hydrophobic membrane;ECTFE membrane;thermally induced phase separation
研究领域:
化学工程
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材料科学
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膜技术
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DOI
PubMed
高影响因子
SURFACE AND INTERFACE ANALYSIS
·
2012
·Vol. 45
·期 3
·698-704
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IF 1.18
Junfei Ou,Weihua Hu,Ying Wang,Fajun Wang,Mingshan Xue,Wen Li
A novel bilayer superhydrophobic film was constructed on Cu substrate by a simple multi-step process. First, (3-mercaptopropyl) trimethoxysilane (MPTMS) molecules were self-assembled onto the pre-etched Cu surface via covalent bonding followed by hydrolysis and condensation, then 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane (PFDTS) were grafted onto the resultant hydroxyl terminated surface via the Si-O-Si bonding. The so-prepared sample was defined as Cu-MPTMS-PFDTS. The structure and morphology of the samples were characterized by means of contact angle measurement, X-ray photoelectron spectroscopy and scanning electron microscopy. The corrosion behaviors of the films were evaluated by Tafel plot and electrochemical impedance spectroscopy on an electrochemical work station. The results indicated that the bilayer superhydrophobic film possessed better corrosion protection as compared with the control samples. The superiority of the corrosion protection was mainly ascribed to the following two aspects: the superhydrophobicity and polysiloxane micro-structures of the Cu-MPTMS-PFDTS. Copyright © 2012 John Wiley & Sons, Ltd.
研究领域:
材料科学
·
腐蚀与防护
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Xianfu Chen,Chaowen Dai,Tianyu Zhang,Peng Xu,Wei Ke,Jian Wu,Minghui Qiu,Kaiyun Fu,Yiqun Fan
Membrane separation has been proven to be a promising technology for waste-oil purification. However, the efficient preparation of hydrophobic and strong membrane materials has always been one of the bottlenecks and the object of research focus in the field. Here, we developed an efficient construction method for preparing a hydrophobic membrane with a robust polytetrafluoroethylene (PTFE) top layer. The macroporous ceramic substrate was applied instead of the ceramic membrane as the support of the PTFE layer. Meanwhile, two-dimensional graphene oxide was introduced to partially pre-fill the large pores on the surface of the substrate. Resultantly, the binding depth between the membrane layer and the substrate was properly tailored. The excessive infiltration of the PTFE membrane layer was avoided, and there was a strong binding between the membrane layer and the ceramic substrate. The effects of the graphene oxide and PTFE loadings and thermal treatment on the microstructure and performance of the composite membrane were systematically studied. The optimized PTFE/alumina composite membrane exhibited a water contact angle of ∼ 135°, an average pore size of ∼ 200 nm, and a layer thickness of 6.5 μm. Additionally, the prepared composite membrane exhibited excellent separation performance for emulsified water and particle suspensions in oil.
研究领域:
材料科学
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环境工程
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产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2020
·
IF 7.183
Yun-Peng An,Chang Liu,Jing Yang,Bian-Bian Guo,Zhi-Kang Xu
Ionic liquids (ILs) show a wide range of applications as “green” solvents in the new era and the recovery of water-soluble ILs has become an urgent issue. Herein, for the first time, osmotic distillation is applied to concentrate and recover water-soluble ILs with a series of hydrophobic membranes. Poly(vinylidene fluoride) membrane with vertically oriented pores and stainless steel mesh were hydrophobically modified and then compared with commercial membranes to demonstrate the influence of different pore structures on the osmotic distillation concentration process . With the vapor pressure difference between two sides of the membrane being the driving force, the dilute aqueous solutions of ILs can be concentrated to about 84 wt % after 24 h with a water flux of 7.8 kg m −2 h −1 . It is also able to achieve ultra-high rejections to ILs and MgCl 2 (>99.99%) by this osmotic distillation process. Although there exists a limitation for dewatering the ILs solutions with very high concentrations and thus the final ILs purity cannot reach 100%, this method is promising for practical applications benefiting from its high rejection to ions, easy operability at ambient temperature and remarkable universality in terms of hydrophobic membranes used.
研究领域:
化学工程
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环境科学
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材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
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2020
·
IF 5.065
Jiaojiao Cao,Chengbin Guo,Xingpeng Guo,Zhenyu Chen
A zeolitic imidazole framework-8 (ZIF-8) derivative was synthesized and developed as the corrosion inhibitor of copper in 0.5 mol/L NaCl solution, and its inhibition performance was investigated by electrochemical measurement and surface analysis . Results show that the ZIF-8 derivative could effectively inhibit copper from corrosion, and the inhibition efficiency was 87.2% at an optimal ZIF-8 derivative concentration of 45 mg/L. The corrosion inhibition mechanism of the ZIF-8 derivative could be explained as follows: the amino functional groups and the π-system formed by aromatic rings of the ZIF-8 derivative were tightly adsorbed on the copper substrates, which systematically formed a hydrophobic film, thereby effectively inhibiting the corrosion caused by aggressive ions.
研究领域:
材料科学
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电化学
·
表面分析
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DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS
·
2019
·Vol. 57
·期 8
·421-430
·
IF 2.596
Guohui Zhang,Panpan Wang,Xiaoxiao Zhang,Chunhui Xiang,Lili Li
Superhydrophobic polycaprolactone (PCL) membranes with hierarchical structure were fabricated via alternate electrospinning/electrospraying techniques. Electrospun PCL/methyl silicone oil (PCL/MSO) nanofibers were employed as substrate. PCL/MSO-PCL microspheres (PCL/MSO-PCL MS ) hierarchical membrane was prepared via electrosprayed PCL MS as an additional layer on the substrate. Field emission scanning electron microscopy images showed the formation of hierarchical PCL/MSO-PCL MS membranes. Compared to pure PCL fibers substrate (120 ± 1.3°), the water contact angle (WCA) of MSO-modified PCL membrane was 142 ± 0.7°. The most interesting observation was that the WCA of PCL MS without any modification could be achieved to 146 ± 2.8°. On this basis, PCL/MSO-PCL MS hierarchical membrane possessed superhydrophobic surface with 150 ± 0.6° of WCA. The excellent surface roughness and air-pocket capacity of hierarchical membranes would make the membranes more hydrophobic. The maximum oil ( n -hexane) adsorption capacity of PCL/MSO-PCL MS membrane was 32.53 g g −1 . Oil–water separation efficiencies of the superhydrophobic membranes were all higher than 99.93% after 10 cycles. The hierarchically structured PCL superhydrophobic membranes indicate the potential applications of environmentally friendly biopolymers as separation membranes. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57 , 421–430
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
Membranes
·
2022
·Vol. 12
·期 8
·743
·
IF 4.562
Yu-Jing Liu,Yan-Nan Lu,Dong-Qing Liang,Yin-Shuang Hu,Yu-Xi Huang
Membrane distillation (MD) has emerged as a promising technology for hypersaline wastewater treatment. However, membrane scaling is still a critical issue for common hydrophobic MD membranes. Herein, we report a multi-layered surface modification strategy on the commercial polyvinylidene fluoride (PVDF) membrane via plasma treatment and surface fluorination cycles. The repeated plasma treatment process generates more reaction sites for the fluorination reaction, leading to higher fluorination density and more branched structures. MD tests with CaSO4as the scaling agent show that the modification strategy mentioned above improves the membrane scaling resistance. Notably, the PVDF membrane treated with three cycles of plasma and fluorination treatments exhibits the best anti-scaling performance while maintaining almost the same membrane flux as the unmodified PVDF membrane. This study suggests that a highly branched surface molecular structure with low surface energy benefits the MD process in both membrane flux and scaling resistance. Besides, our research demonstrates a universal and facile approach for membrane treatment to improve membrane scaling resistance.Keywords:membrane distillation;multi-layered surface modification;scaling resistance;superhydrophobic membrane
研究领域:
环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Guang Xu,Xian Jiang,Fuchao Yang
The increase in the discharge of industrial oily wastewater poses a threat to the environment and human health. Thus, the treatment of oily wastewater has become a focus of current research. The superhydrophobic surface derived from the lotus effect provides an effective direction for oil-water separation. Based on this, the authors reported a tunable superhydrophobic stainless steel separation mesh with a water contact angle of 155° through simple electrodeposition and modification with a fluorine-free modifier. The separation mesh with different surface morphology, by controlling different electrodeposition time and current, is able to achieve oil-water separation with super flux up to 51561 L/(m 2 ·h) in heavy oil/water mixture and high-efficiency over 99.5% in water-in-oil emulsion. This controllable process constructs superhydrophobic membrane with tunable pore size, which is capable of separating heavy oil/water mixtures and water-in-oil emulsions depending on the process. This proposal is suggestive in the field of oil-water separation.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Water Process Engineering
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2024
·
IF 6.3
Minyuan Han,Haoquan Zhang,Yinshuang Hu,Lu Zhou,Chengyue Bian,Yuanyuan Yu,Jingmei Yao,Chun Yang,Zenamarkos Sendekie,Heng Liang,Le Han
Electrified membrane is considered an alternative solution to the trade-off between permeability and fouling/wetting resistance of hydrophobic membranes. Herein, we reported a facile and universal carbon nanotubes (CNT)-based surface coating methodology followed by crosslinking with polyvinyl alcohol (PVA) toward robust electrified hydrophobic membranes. The physicochemical properties including sheet resistance of the as-prepared membranes were scrutinized over a varying mass loading of the CNT and PVA. Serving as the cathode in membrane distillation (MD), the CNT-modified membrane exhibited excellent anti-oil-fouling performance against hexadecane-in-water emulsions of 500 ppm in addition to an improved water vapor flux against brackish water regardless the substrate membrane. In particular, at a cell potential of 3 V, the fouling constant for electrified membrane was reduced up to 100 % compared to the control, with a negligible flux decline by only 4 %. Such a data was in line with the membrane-foulant interactive energy analysis, indicating the significance of the enhanced electro-repulsion with the cell potential applied. Interestingly, the fouling-resistance of polytetrafluoroethylene membrane was significantly improved to a comparable level with the other counterparts, as illustrated by the electrochemical impedance spectroscopy data. This study confirms that the CNT-modification together with an electro-assistance paved the way for electrified hydrophobic membrane of superior fouling resistance.
研究领域:
环境工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2024
·
IF 5.3
Xiaoxin Chen,Ruimeng Han,Zirui Guo,Haobo Ma,Xiaoyu Ji,Lei Wang,Jianwei Meng,Yanyan Fang,Kyongjin Pang,Shan Peng
Metal organic framework (MOF)-derivatives have a larger specific surface area, higher porosity, tunable pore size, higher conductivity, good stability, more exposed active species, etc., but few literature are reported about their application potential in micropollutant separation and removal. In view of this, a robust MOF derivative-based photocatalytic superhydrophobic membrane (D6/TiO2/MoS2/NiCo-NC/PVDF) was successfully fabricated for the first time through solvothermal synthesis and chemical modification, combined with a negative pressure-assisted loading approach. (1) The MoS2-doping strategy effectively avoided the collapse and coarsening of cauliflower-like MOFs during the calcination phase and simultaneously ensured the uniform distribution of metal particles in MOF-derived carbons. (2) The synergistic catalysis of the NiCo-MOF derivative, MoS2, and TiO2 enhanced the transfer efficiency of electrons and free radicals, achieving efficient in situ degradation of pesticides and pharmaceutical and personal care products. (3) The introduction of sodium alginate greatly improved the adhesion between the coating and polyvinylidene fluoride (PVDF) membrane and simultaneously enhanced the growth of MOFs through complexation. (4) The cauliflower-like MOF-derived carbon skeleton with higher surface areas and micronanoporosity combined with a heterogeneous MoS2 structure provided a large specific surface area and enough adsorption sites for various pollutants. High thermal calcination treatment greatly enhanced MOF growth rate, thus resulting in a flaky structure with high regularity and a large specific area. (5) The ultralow surface energy of interlaced siloxane molecules endowed the hybrid membrane with robust superhydrophobicity and superoleophilicity, always maintaining superhydrophobicity after long-time photodegradation. The final membrane achieved continuous emulsion separation and a photocatalytic self-cleaning property. The separation efficiency of the hybrid membrane for emulsions was still up to 97% after reuse for 120 cycles, and it could degrade 86.5% PRO, 90.1% ACE, 92.1% ASP, and 94.3% SMZ, respectively, with the initial concentration of 10 mg/L. The driving forces for oil–water separation and decontamination of the D6/TiO2/MoS2/NiCo-NC/PVDF membrane mainly involved the grasping forces of dodecamethylcyclohexasiloxane, capillary force of inner pores, electrostatic interaction, hydrogen bond interaction, partial p-π conjugation, van der Waals force, and lipophilicity.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED POWDER TECHNOLOGY
·
2024
·
IF 4.2
Chen Jixi,Jia Jinqing,Zhu Mengyu
Water film thickness (WFT) has been discovered to significantly affect the performance of cement-based materials in previous studies. The purpose of this study is to apply the WFT theory to cement-based materials with early-strength agents. To this end, calcium chloride (CaCl 2 ) and triethanolamine (TEA) were used to prepare 32 groups of fresh pastes with varying water-cement ratios and different dosages of CaCl 2 /TEA. These pastes were tested for flow performance, setting time, and hardening performance. The comprehensive effects of WFT and early strength agents on the mobility and hardened properties of cement-based materials were discussed from the obtained results. Results show that WFT is still one of the main elements affecting the performance of cement-based materials in the presence of early strength agents. CaCl 2 increased the packing density of the paste, enhancing the excess water between particles and enlarging the WFT, which positively impacted the performance of the paste. In contrast, TEA decreased the WFT, increased the cohesion between particles, and declined the fluidity. Furthermore, as the water-cement (w/c) ratio raised, the WFT of the paste also increased. This caused cement particles to be enveloped in excess water, improving slip capacity and consequently increasing fluidity but reducing strength. Overall, WFT and admixture dosage can effectively predict the fluidity and mechanical properties of the paste.
研究领域:
土木工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）