Scientific Reports
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2017
·Vol. 7
·期 1
·1-12
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IF 4.259
Xiong Zhu,Lin Haibo,Liu Fu,Xiao Peng,Wu Ziyang,Li Tiantian,Li Dehong
Instability of superwetting surface is the stumbling block of flexible polymeric membranes for continuous separation of water-in-oil or oil-in-water emulsions. Manipulation of rigid superwetting nano-TiO 2 on hierarchical poly(vinylidene fluoride) (PVDF) membrane by mimicking the plant roots holding soil behaviour enabled the generation of robust superwetting surface withstanding the harshly physical and chemical torture. The unique interface combination, which fabricated by a compacted nano-layer with the thickness of ~20 μm, was disclosed by systematic structure characterization. As demonstrated by SEM, LSCM and nano-CT, the pristine PVDF membrane with large quantities of cilia-like micro/nano-fibrils can function as the plant roots to capture, cage and confine the nanoparticles to form a robustly rigid nano-coating. The as-prepared membranes showed excellent durable separation performance both in varieties of stabilized water-in-oil and oil-in-water emulsion separation for a long term with few nanoparticles loss in a continuous crossflow mode. The strategy of assembling rigid inorganic nano-particles on flexible surface offers a window of opportunity for preparation of robust organic-inorganic hybrid membranes not only for continuous oil/water emulsion separation, but also for other functional application, such as electric conduction, heat conduction, ion exchange, and in membrane catalytic reactors etc.
研究领域:
材料科学
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环境工程
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DOI
PubMed
高影响因子
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.
研究领域:
材料科学
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环境工程
·
表面化学
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2025
·
IF 5.4
Ahai Zhu,Jian Zheng,Zhijia Zhu,Chunyan Hu,Baojiang Liu
Oil scaling poses a significant threat to the stability of membrane separation flux during the process of oil-water emulsion separation. A single hydrophilic modified layer demonstrates the capability to effectively separate emulsions. However, it does not prevent severe water flux degradation. Although the “dual-defense” design has been proposed, the construction of a double hydrophilic anti-fouling process on the surface of the membrane is prone to clogging of the membrane, and the surface is difficult to regulate. Here, we designed a two-layer antifouling strategy using vacuum deposition method, in which the first barrier is formed by dopamine (DA) and polyethyleneimine (PEI)-coated carbon nanotubes (CNTs), and the second barrier is formed by a polyelectrolyte complex of phytic acid (PA) and polyethyleneimine (PEI) encapsulating the first barrier, which is deposited on the surface of AT-PVDF membranes. The spatial hierarchical structure provides a highly covered “double defense” barrier on the membrane surface, effectively preventing the adhesion of grease and dirt. In the separation of surfactant-stabilised oil-in-water emulsions, the emulsion separation efficiency reaches 99.8 %, and the water flux recovery rate is more than 90 % after cyclic separation. And the potential mechanism of underwater antifouling self-cleaning was analysed by density flood theory (DFT) calculations. In particular, the multilayer composite membrane was able to effectively adsorb cationic dyes in wastewater through the electrostatic effect of the first and second barriers, with a separation efficiency of more than 95 %. Therefore, the prepared superhydrophilic multilayer composite membrane has potential application prospects in the field of wastewater purification.
研究领域:
材料科学
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环境工程
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DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2020
·
IF 6.551
Changsheng Guo,Haiting Shi,Wei Wang,Xiaoyuan Pei,Kunyue Teng,Yanli Hu,Zhiwei Xu,Hui Deng,Xiaoming Qian
Electret treatment was a simple method to enhance the charge-electrode properties of polyvinylidene fluoride (PVDF) materials due to the increase of space charge and polarization charge of PVDF materials. The polarization charge was due to the electric dipole orientation change in loose nanofiltration PVDF membrane, which increased the electric dipole moment and improved the polarity of surface potential. Importantly, electret charges were less affected by ambient humidity. Therefore, the electret treatment could improve the surface negative potential of loose nanofiltration PVDF membrane, so as to improve its anti-fouling performance under certain conditions. Based on the above theoretical analysis, the influence and mechanism of the electret treatment on the surface potential, morphology, structure, hydrophilicity and anti-pollution performance of PVDF membrane were studied in this manuscript. When the electret time was 7.5 min and the electret voltage was 30 kV, the surface negative potential was the highest. The content of β phase crystals was 39.1%, which was 12.18% higher than that of untreated membrane. In addition, the surface morphology of PVDF membrane did not change significantly, but the water contact angle decreased slightly, and the pore size increased by 0.36–0.75 nm. Importantly, the flux and the rejection of dye and BSA increased to some extent, and the maximum rejection rate and water flux were increased by 10.34% and 20.25%, respectively. Through the cyclic filtration test and analysis, the anti-fouling performance of membrane was increased due to electrostatic repulsion.
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
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Honghe Song,Haiyan Zhu,Rui Wang,Shumei Wen,Chenghu Yan,Wei Cong
We propose a facile method for preparing polyvinylidene fluoride (PVDF) membranes with exceptional selectivity for rare earth ions and stability by UV irradiation technology using 3,3′, 4,4′-benzophenone tetracarboxylic acid (BTA) as the grafted materials. The grafting of BTA onto the membrane surface was confirmed through Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The selection factors of PVDF- g -BTA membranes for Dy 3+ over Na + , K + , Ca 2+ , and Mg 2+ were 140.57, 114.16, 74.23, and 86.25, respectively. The adsorption capacity of the PVDF- g -BTA membranes remained above 80 % following five adsorption–desorption cycles, and the contact angle remained stable throughout the 30 days of immersion.
研究领域:
材料科学
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环境工程
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Tingting Liu,Lei Wang,Xiu Liu,Chenxu Sun,Yongtao Lv,Rui Miao,Xudong Wang
The dynamic photocatalytic membrane coated with ZnIn 2 S 4 was fabricated to solve the problems of suspended photocatalyst separation and membrane fouling that occur in applying photocatalytic technology and membrane separation technology, respectively. The structural characteristics, photocatalytic performance, and antifouling property of dynamic photocatalytic membranes with different loadings of ZnIn 2 S 4 were systematically investigated. As the loading of photocatalysts increases, a uniform and dense photocatalytic layer formed on the membrane surface, and the surface morphology changed from a protruding structure to an undulating mountain-like structure. The roughness and absorption performance for UV–Vis of dynamic photocatalytic membranes increased because of the formation of a photocatalytic layer while the chemical property and water flux did not change. The removal efficiencies of fluvastatin and total organic carbon by dynamic photocatalytic membranes were significantly increased compared with that of the pristine polyvinylidene fluoride (PVDF) membrane, indicating that the dynamic photocatalytic membranes possessed excellent photocatalytic performance and high stability. Meanwhile, the dynamic photocatalytic membranes exhibited a greater antifouling property than the pristine PVDF membrane because of the formation of the photocatalytic layer on the membrane surface. Therefore, the fabrication of dynamic photocatalytic membrane is an effective method to promote the advantageous combination of photocatalytic technology and membrane separation technology.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
WATER RESEARCH
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2017
·
IF 6.942
Yan-Fang Guan,Bao-Cheng Huang,Chen Qian,Long-Fei Wang,Han-Qing Yu
Polyvinylidene fluoride (PVDF) membrane has been widely applied in water and wastewater treatment because of its high mechanical strength, thermal stability and chemical resistance. However, the hydrophobic nature of PVDF membrane makes it readily fouled, substantially reducing water flux and overall membrane rejection ability. In this work, an in-situ blending modifier, i.e., extracellular polymeric substances (EPS) from activated sludge , was used to enhance the anti-fouling ability of PVDF membrane. Results indicate that the pure water flux of the membrane and its anti-fouling performance were substantially improved by blending 8% EPS into the membrane. By introducing EPS, the membrane hydrophilicity was increased and the cross section morphology was changed when it interacted with polyvinl pyrrolidone, resulting in the formation of large cavities below the finger-like pores. In addition, the fraction of pores with a size of 100–500 nm increased, which was also beneficial to improving membrane performance. Surface thermodynamic calculations indicate the EPS-functionalized membrane had a higher cohesion free energy, implying its good pollutant rejection and anti-fouling ability. This work provides a simple, efficient and cost-effective method to improve membrane performance and also extends the applications of EPS.
研究领域:
环境工程
·
污水处理
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DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2022
·
IF 10.53
Chenxin Tian,Jiansuxuan Chen,Xianfeng Li,Ruobin Dai,Zhiwei Wang
Membrane will inevitably reach its end of life during long-term application. The current disposal approach of replacing end-of-life (EOL) membranes by new membranes constrains the economic efficiency and sustainability of the membrane-based wastewater treatment . Herein, we conducted a proof-of-concept study of regenerating EOL polyvinylidene fluoride (PVDF) membranes from a full-scale membrane bioreactor (MBR), to achieve an economical and sustainable membrane-based wastewater treatment. A novel chemical cleaning−solvent treatment−hydrophilic modification strategy was proposed for regenerating the EOL PVDF membranes. After the regeneration, the water permeance of the EOL membrane could be recovered from 43.7 ± 8.8 to 426.0 ± 40.3 L m −2 h −1 bar −1 , which was comparable with that of the new membrane. The solvent treatment slightly dissolved the membrane matrix and facilitated the detachment of recalcitrant foulants, which was responsible for the markedly recovered water permeance. The hydrophilic modification using polydopamine coating effectively improved surface hydrophilicity of membrane, endowing the regenerated membrane with better antifouling performance over the solvent treated membrane. The regenerated membrane was tested in an MBR for real municipal wastewater treatment, where the regenerated membrane possessed a comparable effluent quality, as well as a lower fouling rate over EOL, chemical cleaned, and solvent treated membranes. Compared with the conventional way of membrane replacement, the reduction in expenditure and carbon emission of membrane regeneration was ∼3.0 USD/m 2 -membrane/year and 0.059 kg CO 2 -e/membrane module, respectively. This proof-of-concept study offers a promising strategy of the EOL membrane regeneration to achieve economical and sustainable membrane-based wastewater treatment.
研究领域:
环境科学
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废水处理
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材料科学
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产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2023
·
IF 5.2
Jie Hu,Shenglin Yuan,Wensha Zhao,Caiwang Li,Peng Liu,Xiang Shen
The direct discharge of oily wastewater into the environment is considered one of the greatest threats to the ecological environment. Membrane technology is considered as an efficient strategy to treat oily wastewater. However, the membrane fouling caused by oil adsorption has intensively impeded its practical utilization in oil/water separation. This work aims to fabricate an anti-oil-fouling membrane for the effective separation of oil/water emulsions. The PEGylated poly(vinylidene fluoride) (PVDF) membrane was synthesized via thiol–ene photochemistry with poly(ethylene glycol) diacrylate (PEGDA) and 3,6-dioxa-1,8-octanedithiol (DOT) as the modifiers. The results of scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) mapping analysis revealed that the PEGylated layers show uniform distribution on the membrane surface by regulating the feed PEGDA concentration. The superhydrophilic and underwater superoleophobic characteristics of the PEGylated membrane provided oil-adhesion resistance to the membranes. The membrane grafted with a high amount of PEGylated layers shows a low pure water flux, due to the pore blockage. The PEGylated membrane possesses the stable surface wettability and permeation performance of emulsion. The separation efficiency of PEGylated membranes for multiple emulsions is greater than 99%, and the highest rejection value is as high as 99.9%. After the three-cycle filtration of emulsified pump oil solution, the flux recovery ratio of membranes still reaches 90%, indicating an outstanding fouling resistance to emulsified oily matters. This work provides a feasible strategy to prepare the antifouling PVDF membrane used for the oil/water separation.
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
CHEMOSPHERE
·
2023
·
IF 8.8
Jun Young Kim,Kang Hoon Lee,Jae Won Lee,Imtiaz Afzal Khan,Jong-Oh Kim
In this study, the removal efficiency of chemicals of emerging concerns (CECs) was evaluated under exposure to various doses of UV/H 2 O 2 -based oxidation processes in combination with membrane filtration for three cleaning cycles. Polyethersulphone (PES) and polyvinylidene fluoride (PVDF) materials based membranes were used for this study. The chemical cleaning of the membranes was performed by immersion of the membranes into 1 N HCl followed by adding 3000 mg.L −1 NaOCl for 1hr. Degradation and filtration performance was evaluated using Liquid Chromatography with tandem mass spectrometry (LC-MS/MS) and total organic carbon (TOC) analysis. Membrane fouling analysis for assessing the comparative performance of PES and PVDF membranes was determined by specific fouling and fouling indices evaluation. Membrane characterization results show that the alkynes and carbonyl group formation are due to dehydrofluorination and oxidation of PVDF and PES membranes under the attack of foulants and cleaning chemicals, which resulted in a reduction of fluoride percentage and an increase in sulfur percentage in the PVDF and PES membranes. A decrease in the hydrophilicity of the membranes in underexposed conditions was observed and is consistent with an increase in dose. Degradation results of CECs follow with the highest removal efficiency of chlortetracycline (CTC) followed by atenolol (ATL), acetaminophen (ACT), and caffeine (CAF) degradation due to attack on the aromatic ring and the carbonyl group of CECs by OH exposure. Membrane exposed at 3 mg.L-1 dose of UV/H 2 O 2 -based CECs shows minimum alteration with higher filtration efficiency and lower fouling, particularly in PES membranes.
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
MATERIALS RESEARCH BULLETIN
·
2022
·
IF 5.6
Qianyu Wei,Qiuhu Lin,Zezhen Zhang,Lili Wu,Chaocan Zhang
Polyvinylidene fluoride (PVDF)/polyhexamethylene guanidine (PHMG)/tannic acid (TA) coatings have some degree of hydrophilicity but lack stability. To improve the hydrophilicity and stability of antimicrobial PVDF/PHMG/TA membranes, Fe(III) is introduced into the composite system. As a weakly acidic hydrophilic nanoion, Fe(III) can enhance the hydrophilicity and resistance to contamination of the membranes. Furthermore, the stability can be enhanced because a three-dimensional cross-linked coating structure is formed by the complexation of Fe(III), TA and PHMG. This work investigates the effects of different tannic acid concentrations and pH conditions on the hydrophilicity, anti-pollution and stability of the modified coatings. The surface morphology of the membranes was analyzed by field-emission scanning electron microscopy. Additionally, the hydrophilicity and the antipollution performance were evaluated based on the water contact angle, submerged oil contact angle, emulsion flux and flux recovery rate. The stability was evaluated by the changes in flux recovery rate and water contact angle before and after emulsion scouring and ultrasonic treatment. The results show that the modified membranes have favorable hydrophilicity and stability after the addition of Fe(III). The water contact angle can be reduced to 19°, the pure water flux can reach 13,850 L·m −2 ·h −1 , and the emulsion flux can reach 2650 L·m −2 ·h −1 . Moreover, 99.68% flux recovery was achieved after 7 days of deionized water flushing, and the water contact angle remained almost unchanged.
研究领域:
材料科学
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环境工程
·
界面化学
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产品关联
DOI
高影响因子
LANGMUIR
·
2023
·
IF 3.9
Yujia Tong,Changing Miao,Wenlong Ding,Fiona Hammond Quarcoo,Xiao Xiao,Hongjun Ji,Weixing Li,Xiaohui Ju
The current methods of constructing modification strategies for hydrophilic membranes are time-consuming, complex in operation, and poor in universality, which limit their application on membranes. In this work, inspired by the adhesion properties and versatility of caffeic acid (CA) and p-phenylenediamine (PPDA), a simple, rapid, and universal method was designed for the separation of oil-in-water emulsion by preparing a stable hydrophilic coating separation membrane. The preparation time of the membrane was shortened to 40 min. The developed PVDF–PCA/PPDA membrane showed superhydrophilic and underwater superoleophobic properties. When applied to petroleum ether-in-water emulsion, isooctane-in-water emulsion, and dodecane-in-water emulsion separation, the oil rejection was more than 99.0%. In the circulating separation of 10 g/L soybean oil-in-water emulsion, the oil rejection was more than 99.3%, and the highest flux was 1036 L·m–2·h–1. The prepared PVDF–PCA/PPDA membrane performed well in the separation test of oily wastewater. The proposed strategy is simple and rapid; it may become a universal method for preparing membranes with super strong antifouling properties against viscous oil and accelerate the research progress of membrane separation of oil-in-water emulsions.
研究领域:
材料科学
·
环境工程
·
界面化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）