JOURNAL OF MEMBRANE SCIENCE
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2020
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IF 7.183
Liang Cheng,Mengxiao Zhang,Chuanjie Fang,Weilin Feng,Liping Zhu,Youyi Xu
Loose nanofiltration (NF) membrane with pore radius approaching 1 nm and positive charges can be valuable alternative to commercial available negatively charged polyamide NF membrane in specific applications, such as removal of hardness and heavy metal ions and selective separation of dyes/salts mixture. In this work, positively charged poly( N -vinyl imidazole) (PVI) gel-filled loose NF membranes were developed by asymmetric gel-filling upon an asymmetric ultrafiltration (UF) support via UV-initiated surface grafting polymerization and post-quaternization. Compared to the polyamide NF membranes, these membranes displayed a comparable salt rejection ability due to their stronger Donnan exclusion effect. A rigorous three-parameter transport model (TPM) considering steric, Donnan and dielectric exclusion on ions partitioning via effective pore radius ( r p ), membrane charge density ( X d ) and averaged pore dielectric constant ( ε p ), was used to analyze the membrane parameters. Then the gel conformation model (GM) treating confined gel as semi-dilute polymer solution with a characteristic correlation length ( ξ ) was applied to analyze these gel composites. The results suggest that the gel polymer volume fraction ( φ ) is decisive in the gel mesh size (viewed as membrane pore size) and gel permeability. Surface porosity of the asymmetric UF base is a limiting factor in membrane permeability. The joint modelling analysis can clarify the membrane structure-properties relationship, performance limits and potentials of the gel-filled NF membrane and hence facilitate structure design and optimization.
研究领域:
化学工程
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材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 42
·e56112
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IF 2.7
Xunwang Tang,Zongxue Yu,Junlei Tang,Jiaqiang Huang,Xiuzhu Zhang,Jiajia Hou,Guangcheng Yang
The durability of anion exchange membranes (AEMs) and the balance between ionic conductivity and dimensional stability have been the focus of research. To this end, we propose a new type of AEMs with vinyl imidazole as the in situ cross-linking monomer. The rigid-flexible balance within the membrane was adjusted by changing the arrangement of the internal segments of the polymer and introducing different monomers into the main chain. The results showed that the performance of AEMs could be effectively improved by adopting an ether-free backbone and a cationic cross-linking strategy. The swelling rate of all AEMs was less than 20%. The ionic conductivity of BDCP-80 reached 102.74 mS cm −1 at 80°C. Alkaline stability tests showed that the ionic conductivity of all AEMs remained above 82% after 720 h immersion in 2 M NaOH solution at 80°C. This study demonstrated that the simple in situ cross-linking method can effectively improve the overall performance of AEMs and provide an effective way to develop high-performance AEMs.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2018
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IF 5.091
Chuanjie Fang,Jian Sun,Bin Zhang,Yuchen Sun,Liping Zhu,Hideto Matsuyama
Developing nanofiltration (NF) membranes with highly efficient and precise separation ability is of great significance for the molecular and ionic separations. In this work, positively charged composite NF membranes were engineered via soaking of polysulfone (PSF) ultrafiltration membranes in poly( N -vinyl imidazole) (PVI) solutions followed by a quaternization crosslinking step. The PVI was firmly attached to the PSF membrane by this method and acted as an active separation layer of the composite NF membrane. The obtained composite NF membrane featured a high rejection (83%) to vitamin B 12 (molecular radius: 0.74 nm) but a low rejection (24.6%) to vitamin B 2 (molecular radius: 0.47 nm), exhibiting a great potential in precisely molecular separation. Furthermore, the ionic separation ability of the composite NF membrane was confirmed with a rejection order of Na 2 SO 4 < MgSO 4 < NaCl < MgCl 2 and the MgCl 2 rejection reached up to 90.1%. Compared to conventional polyamide NF membranes, the developed PVI/PSF composite NF membranes were characterized with high separation precision to organic molecules, higher rejection over cationic ions than over anionic ones, better chlorine resistance and stability in long-term operation. In addition, the membrane fabrication process is convenient and easily scaled up in industry. This work offers a novel alternative of NF membranes for high precision in molecular and ionic separations.
研究领域:
材料科学
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膜技术
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环境工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2015
·
IF 5.056
Liang Cheng,Li-Ping Zhu,Pei-Bin Zhang,Jian Sun,Bao-Ku Zhu,You-Yi Xu
Here we demonstrate the tunable molecular selectivities and corresponding mechanisms of poly(N-vinyl imidazole) (PVI) gel-filled membranes prepared by UV initiated graft polymerization of N-vinyl imidazole from ultraporous polysulfone (PSf) substrate. The separation performance was investigated in detail by extensive filtration tests with various organic molecules in water of varying pH and also in salt or ethanol aqueous solution. The variation of membrane water permeability and solute rejection with the feed pH was attributed to the sensitive pore size and charge characteristics of the membranes upon reversible protonation of the confined PVI gel. The separation results discerned three main mechanisms, i.e. size exclusion (sieving), electrostatic repulsion (Donnan exclusion) and adsorption. The rejection of the neutral molecules and the large dye molecules was mostly ascribed to size exclusion, while that of the small charged solutes was dominated by the electrostatic interactions including repulsion for cationic ones and attraction for anionic ones (causing specific adsorption). Typically, at pH 3 the protonated membranes rejected ~90% of the small cationic Vitamin B 1 (VB 1 ) and 100% of the anionic Sunset Yellow (SY) before adsorption saturation, in contrast to less than ~20% rejection of the neutral Vitamin B 2 (VB 2 ) having similar molecule size. In the high concentration salt or ethanol solution the membranes still maintained molecular sieving capability. Most notably, the separations of solute mixtures were indeed achieved, depending on the membrane parameters, the solute characteristics as well as the filtration conditions. The PVI gel-filled membranes developed in this work are promising in some specified or environment-sensitive molecular level separations.
研究领域:
材料科学
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环境工程
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化学工程
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2025
·
IF 9
Zijie Zhao,Kefan Ren,Lei Wu,Jiahou Hao,Ming Li
Ultrafiltration (UF) membrane is a core technology for wastewater treatment, but membrane fouling causes a decline in their flux and shortens their service life, making it a key bottleneck issue. In this study, polyvinylimidazole (PVIm) was loaded onto the surface of polyvinylidene fluoride (PVDF) membranes to prepare antibacterial UF membranes by utilizing the adhesion effect of polydopamine (PDA). The inhibitory ability of the modified membrane against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) was studied using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The experimental results show that 10 % PVIm was the optimal dosing for UF membrane modification (defined as M10 membrane). The M10 membrane exhibited an outstanding antibacterial ability of 79.2 % for E. coli and 68.5 % for S. aureus , respectively. Meanwhile, its surface was smoother and had a higher pure water flux, which could be a good candidate for water and waste water treatment. In summary, PVIm modified UF membranes are simple to prepare with good antibacterial capacities, providing an effective and promising strategy for wide application in urban sewage treatment.
研究领域:
环境科学
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材料科学
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化学工程
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微生物学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2025
·Vol. 18
·期 15
·3624
·
IF 3.2
Yanwen Ren,Qianqian Zheng,Cuicui He,Jingjing Nie,Binyang Du
Aqueous organic redox flow batteries (AORFBs) represent an advancing class of electrochemical energy storage systems showing considerable promise for large-scale grid integration due to their unique aqueous organic chemistry. However, the use of small-molecule active materials in AORFBs is significantly limited by the issue of stability and crossover. To address these challenges, we designed a high-water-solubility polymer cathode material, P-T-S, which features a polyvinylimidazole backbone functionalized with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and sulfonate groups. P-T-S exhibits a solubility of 34 Ah L−1in water and 31 Ah L−1in 1.0 M NaCl aqueous solution (NaClaq). When paired with methyl viologen to assemble a pH-neutral AORFB with a theoretical capacity of 15 Ah L−1, the system exhibits a material utilization rate of 92.0%, an average capacity retention rate of 99.74% per cycle (99.74% per hour), and an average Coulombic efficiency of 98.69% over 300 consecutive cycles at 30 mA cm−2. This work provides a new design strategy for polymer materials for high-performance AORFBs.
研究领域:
储能
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电化学
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聚合物材料
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可再生能源
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电池技术
✓ 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）