JOURNAL OF MEMBRANE SCIENCE
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2018
·
IF 6.578
Jiantao Wang,Ruizhang Xu,Feng Yang,Jian Kang,Ya Cao,Ming Xiang
In this work, the influences of polysulfone (PSf) support layer on the morphology of polyamide (PA) selective layer was investigated. Interfacial polymerization was conducted on PSf support layers with different surface pore size or at the bulk interface. The bottom surface of PA layer was exposed by carefully dripping N , N -dimethylformamide onto the back side of thin film composite membranes . Morphological study showed that the porous structure of the bottom surface of PA layer was always accompanied by PSf layer with small surface pores. Conversely, when synthesized on PSf layer with large surface pores or at the bulk interface, this porous structure turned into featureless flat areas. In addition, the top side ridge-and-valley structure was also found to be linked to the porous structure on the bottom side. Based on the observations, a “nascent particles aggregation” model was proposed. By investigating how the morphology of PA layer was swayed by PSf layer, better understanding regarding the correlation between membrane performance and support layer properties could be obtained.
研究领域:
材料科学
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膜技术
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2024
·
IF 8.4
Jiakai Chen,Hongchang Pei,Yan Zou,Huiying Ding,Zhongfang Li,Lei Zhang,Hongsen Hui,Qiang Liu,Xianhui Li,Nozipho Nonsikelelo Gumbi,Luchang Qin
In the preparation of nanofiltration (NF) membranes, the introduction of acid acceptors into the aqueous phase generates heat through their interaction with the byproduct HCl from interfacial polymerization (IP), potentially leading to the formation of bubbles. This work aims to dissect the combined influences of heat and nanobubbles on NF membrane structure and performance. Three representative alkalis (i.e., NaHCO 3 , NaOH, and Ca(OH) 2 ) were employed as acid acceptors into the aqueous phase, resulting in an increase of the consumption of PIP in the IP reaction from 10.75% to 23.65%, 19.35%, and 12.90%, respectively. The use of NaOH and Ca(OH) 2 released more heat led to a thicker polyamide layer which reduced flux. While the use of NaHCO 3 simultaneously released heat and bubbles, which promoted the development of a rougher surface polyamide layer, resulting in an increased flux from 20.3 to 28.3 L/m 2 h bar, while maintaining a salt rejection rate of 97.7%. The attendance of acid acceptors also enhanced the degree of crosslinking and resulted in a decrease in negative charge of the prepared membrane. This study advances the understanding of the impact of heat and bubbles release induced by the addition of acid acceptors on NF membrane structure and performance.
研究领域:
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 MEMBRANE SCIENCE
·
2024
·
IF 8.4
Xin Wu,Qingqing Guo,Yanhong Ji,Mohammad Younas,Benqiao He
The surface properties of non-porous areas (>90 %) of support membranes were often overlooked to influence the performance of nanofiltration (NF) membranes. In this work, the role of the support membrane in interfacial polymerization (IP) during synthesis of NF membrane and consequently on its performance were quantitatively investigated from the perspective of adhesion force for the first time. The support membranes with considerable pore structures and different surface sulfonate (-SO 3 - ) contents were prepared from different concentrations of polyethersulfone/sulfonated polysulfone (PES/SPSf) solutions. The adhesion forces of different support membranes were measured by atomic force microscope (AFM). The IP process between piperazine (PIP) and trimethylbenzoyl chloride (TMC) and the obtained polyamide (PA) layer on the support membranes were monitored by Quartz crystal microbalance with dissipation (QCM-D). The results indicated that the contents of sulfonic groups on the surface of the support membranes decreased as the casting-solution concentration increased (from 16 % to 28 %) due to a negative segregation phenomenon, which resulted in a decrease in the adhesion force (from 17.9 to 2.6 nN) between the support membranes and PIP monomers. The reduced adhesion force between the support membrane and PIP monomers led to an increase in the PA layer thickness (from 0.8 to 18 nm). Interestingly, the time to reach PA layer thickness equilibrium decreased (from 91 to 23 s). The obtained NF membranes (from PA@PES/SPSf 16 to PA@PES/SPSf 28 ) achieved the pure water permeance from 51.2 to 26.2 L m −2 h −1 ·bar −1 while the salt (Na 2 SO 4 ) rejection from 97.5 to 99.5 %, respectively, was noted. It was demonstrated that controlling the adhesion force between the support membranes and PIP monomers could effectively regulate the structure and the performance of NF membranes. This work would provide valuable insights for designing high-performance NF membranes in practical applications.
研究领域:
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
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Chengling Bai,Zhengyang Gu,Xuerui Gao,Ruijun Zhang,Jingwen Tang,Qian Xiao,Shuili Yu,Rongsheng Ning
Piperazine (PIP)-based polyamide (PA) nanofiltration (NF) membranes exhibit limited rejection of divalent cations due to their negatively charged surfaces and insufficient compactness, restricting their broader application in various water treatment processes. To overcome this challenge, a novel strategy—stepwise increasing TMC concentration (SITC) during the interfacial polymerization (IP)—was proposed to optimize the PA layer structure. Conventional PA layer demonstrates a vertical diffusion structure: a compact barrier region underneath a thick and loose region. The regulatory goal of SITC is to enhance compactness while minimizing the increase in hydraulic resistance. The regulatory mechanism suggested SITC could regulate the IP reaction in both over time (throughout the IP process) and across the reaction region. During the initial IP stage, SITC reduced the reaction rate and increased PIP/TMC ratio in the bottom reaction zone, thereby improving the compactness and potential of final bottom barrier region. Thus, SITC can effectively restrict the permeation of cations, significantly increasing MgCl 2 rejection from 33.70 % to 92.12 %. In the subsequent diffusion-limited stage, SITC enhanced the restriction on PIP diffusion, decreasing the thickness of the final upper loose region and surface potential. Those advantageous characteristics allowed the membrane to maintain a high rejection for Na 2 SO 4 (>98.44 %). Concurrently, the membrane maintained a high water permeance (13.00 L·m −2 ·h −1 ·bar −1 ), attributed to the thin (16.69 nm) and optimized compactness distribution of its PA layer. This study provided a novel mechanism insight into the functional customization of NF membranes by decoupling the synthesis-property-performance relationship.
研究领域:
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
·
2018
·Vol. 136
·期 8
·47102
·
IF 1.901
B.-Q. Huang,H. Ding,Z.-L. Xu,Y.-J. Tang
In this work, the biomacromolecule, single-stranded deoxyribonucleic acid (ssDNA) was innovatively incorporated into the polyamide layer to tailor the permeate flux and antifouling performance of the nanofiltration (NF) membranes. With active amines groups, the ssDNA was as the aqueous phase monomers along with piperazine (PIP), and reacted with trimesoyl chloride on polyethersulfone substrate to fabricate thin-film composite (TFC) NF membranes. The NF membrane prepared under optimal ratio of ssDNA/PIP had a pure water permeability of 75.8 L m −2 h −1 (improved 58% compared to PIP NF membrane) and Na 2 SO 4 rejection of 98.0% at 6.0 bar. The rejections for different inorganic salts were the order: Na 2 SO 4 (98.0%) > MgSO 4 (89.2%) > MgCl 2 (72.8%) > NaCl (23.0%). Furthermore, the TFC NF membranes showed good antifouling performance in long-term running with 300 ppm bovine serum albumin and humic acid solution. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 47102.
研究领域:
材料科学
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环境工程
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生物化学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2022
·
IF 9.136
Yue Zong,Ruijun Zhang,Shanshan Gao,Jiayu Tian
Reducing the thickness of the polyamide (PA) layer has been confirmed as a feasible strategy to improve the permeability of the thin film composite (TFC) nanofiltration (NF) membrane. In this study, a novel interfacial polymerization (IP) approach assisted by the volatilization of n-hexane was proposed to promote the formation of a thinner PA layer, in which a small amount of n-hexane was added onto the substrate membrane after aqueous phase immersion and before the organic phase coating, then the temperature of the substrate membrane together with the water-soluble monomer solution would be decreased due to the volatilization of n-hexane. The infrared thermographies demonstrated that 7.8 μL cm −2 n-hexane dosage was the most efficient, which can sharply decrease the surface temperature from room temperature (25 °C) to 7.9 °C. The TFC membranes prepared at the lower temperature presented much higher permeability. When PIP concentration was 0.3% w/v, TMC concentration was 0.1% w/v and IP reaction time was 40 s, the PA layer formed at this low temperature was smoother and more hydrophilic. Its thickness was reduced from 26.97 nm to 11.98 nm and water permeability was increased by 50% to 36.7 L m −2 h −1 bar −1 while maintaining Na 2 SO 4 rejection of 96.5%.
研究领域:
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 MEMBRANE SCIENCE
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2023
·
IF 9.5
Liu-Kun Wu,Zhen-Liang Xu,Min Tong,En-Chao Li,Yong-Jian Tang
In recent years, the incorporation of nanoparticles in nanofiltration membranes has received extensive attention as a practical approach to improve membrane performance. However, previous studies attributed the enhancement of TFN membrane performance primarily to the advanced properties of nanoparticles and the structural impact on the polyamide layer, while ignoring the influence and contribution of the substrate. This study provides compelling evidence that the effect on the substrate of blending nanoparticles contributes to the enhancement of membrane permeability. We quantified the changes in permeation resistance composition of the TFC and TFN membranes before and after heat treatment by a resistance-in-series model, combined with the addition of polyvinylpyrrolidone. After incorporation of ZIF-8, the permeation resistance of substrate decreased from 0.177 h bar m −1 to 0.0313 h bar m −1 after heat curing, while that of PA layer decreased from 0.1375 h bar m −1 to 0.0972 h bar m −1 . In addition, we removed the PA layer of TFC and TFN membranes by acid hydrolysis. The results indicated that the PWP of TFN membrane were continuously greater than that of the TFC membrane, which supports our conclusion that nanoparticles impacted the shrinkage of substrate during heat curing. The current study provides a novel mechanistic understanding of the improvement of TFN membrane performance by nanoparticles.
研究领域:
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 MEMBRANE SCIENCE
·
2022
·
IF 10.53
Yuehua Zhang,Peng Xu,Xianfu Chen,Minghui Qiu,Yiqun Fan
Thin-film composite (TFC) nanofiltration (NF) membranes have been widely used in water purification processes. In harsh conditions, however, the application of TFC membrane was limited by selectivity loss because of swelling or dissolution. In this study, a defect-free polyamide (PA) layer was directly prepared on a tubular alumina ceramic membrane with a pore size of 100 nm to compensate these shortcomings. The ceramic support, owing to its superior hydrophilicity, showed excellent affinity with aqueous diamine monomers , preventing defects caused by large pore sizes. Besides, the narrow aperture distribution of support is conductive to control the water-oil interface at an appropriate position that the active layer can form near the support by simple air-drying. Different morphologies and performances were easily obtained by changing the monomer concentration and reaction time. The resulting organic–inorganic composite membrane exhibited pure water permeance of 21.7 LMH/bar and desirable rejection to Na 2 SO 4 of 99.0%. Moreover, the prepared NF membrane showed satisfactory compaction resistance at pressure from 2 to 12 bar owing to the excellent mechanical strength of the support. The inorganic support also endowed the TFC membrane with good performance stability even at 75 °C and after soaking in different organic solvents for one week.
研究领域:
材料科学
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环境工程
✓ 已验证
DOI
高影响因子
DESALINATION
·
2025
·
IF 9.8
Xinyi Zhang,Zhaoqing Lu,Doudou Ning,Nan Li,Kaiyue Huang,Dinggen Hu,Songfeng E
Nanofiltration (NF) membranes hold considerable promise for desalination and water reuse. However, the trade-off between permeability and selectivity restricted their efficient applications. Herein, we successfully prepared thin-film nanocomposite NF membranes with mica nanosheets interlayer (M-TFNi) by introducing polyethyleneimine-modified mica nanosheets between the porous support layer and the polyamide (PA) layer, which exhibited superior permeance along with high divalent salt rejection. Owing to the “tortuous effect” of PEI-mica nanosheets and hydrogen bonding interactions, the diffusion rate of piperazine (PIP) was slowed down, which resulted in the formation of a thinner and looser PA layer with higher surface roughness and hydrophilicity. The optimized M-TFNi membrane demonstrated an exceptional permeance of 16.24 L m −2 h −1 bar −1 in 1000 ppm Na 2 SO 4 solution at pH of 8 and a high Na 2 SO 4 rejection of 98.8 % at 4 bar, which is enormously higher than that of the pristine NF membrane without the PEI-mica nanosheets as interlayer. Overall, this work devised a new approach to fabricating high-performance NF membranes for efficient water purification.
研究领域:
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 MEMBRANE SCIENCE
·
2024
·
IF 8.4
Xiaojuan Wang,Houkang Pu,Hanjing Xue,Huacheng Xu,Yijun Huang,Xinyan Wang,Congjie Gao,Xueli Gao
The robust correlation between the performance of thin-film composite (TFC) reverse osmosis membranes and the polyamide (PA) active layer determines the necessity of precise design of the PA layer, and this regulation primarily involves the surface morphology and internal characteristics of the PA layer. In this study, we fabricated honeycomb Turing structure or nanovoid-rich TFC series membranes using polar/nonpolar organic phase additives. Characterization and simulation results confirmed that the enhancement of membrane performance relied more on the abundant nanovoids within the PA layer rather than the ordered honeycomb lattice surface. Notably, the TFC-nDCE membrane with multilayer nanovoids exhibited an approximately 89 % improvement in water permeability while maintaining satisfactory salt rejection (98.29 %). We emphasized the significant role of nanovoids in the diffusion process of amine monomers and investigated the potential relationship between nanovoids and the degree of surface cross-linking. Building upon this, a new insight into the formation of nanovoids induced by PA anisotropic growth was presented through a careful analysis of the amine monomer diffusion rate and the morphological evolution of nanovoids. The structure-property relationship between internal structures, surface morphologies, and performances was systematically and thoroughly investigated, pointing out the direction for the rational design of TFC membranes .
研究领域:
材料科学
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膜技术
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Ming Li,Xuemeng Zhang,Dongqing Wang,Xiaofei Fan,Qianyong Cao,Huining Xiao,Shiwei Guo,Chungang Yuan,Yuling Zhang
Nanofiltration membranes are extensively implemented in water treatment, particularly for the efficient interception of toxic heavy metal ions. This work introduces a novel functional membrane fabricated via interfacial polymerization, incorporating nitrogen and sulfur co-doped carbon dots (N, S-CDs) as additives to enhance mercury removal from aqueous solutions. The integration of carbon dots has been demonstrated to significantly augment the membrane’s hydrophilicity, thereby improving the pure water flux. Moreover, it modulates the crosslinking degree of the polyamide layer, enhancing mercury retention. The N, S-CDs, due to their high selectivity for Hg (II), confer the modified membrane with fluorescence detection capabilities, allowing for the precise quantification of mercury rejection. The membrane achieved a remarkable Hg (II) retention rate of 94.85 %, with a pure water flux of 10.68 L m −2 h −1 bar −1 , and attained a detection limit of 5.49 × 10 −7 M for Hg (II). The durability and reusability of the membrane are substantiated by soaking and recycling trials, underscoring the stable encapsulation of N, S-CDs within the nanofiltration matrix.
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
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2020
·
IF 7.864
Xiaoxiao Song,Bowen Gan,Saren Qi,Hao Guo,Chuyang Y. Tang,Yong Zhou,Congjie Gao
Transport of water, solutes, and contaminants through a thin film composite (TFC) membrane is governed by the intrinsic structure of its polyamide separation layer. In this work, we systematically characterized the nanoscale polyamide structure of four commercial TFC membranes to reveal the underlying structure–property relationship. For all the membranes, their polyamide layers have an intrinsic thickness in the range of 10–20 nm, which is an order of magnitude smaller than the more frequently reported apparent thickness of the roughness protuberances due to the ubiquitous presence of nanovoids within the rejection layers. Tracer filtration tests confirmed that these nanovoids are well connected to the pores in the substrates via the honeycomb-like opening of the backside of the polyamide layers such that the actual separation takes place at the frontside of the polyamide layer. Compared to SW30HR and BW30, loose membranes XLE and NF90 have thinner intrinsic thickness and greater effective filtration area (e.g., by the creation of secondary roughness features) for their polyamide layers, which correlates well to their significantly higher water permeability and lower salt rejection. With the aid of scanning electron microscopy, transmission electron microscopy, and tracer tests, the current study reveals the presence of nanosized defects in a polyamide film, which is possibly promoted by excessive interfacial degassing. The presence of such defects not only impairs the salt rejection but also has major implications for the removal of pathogens and micropollutants.
研究领域:
材料科学
·
环境工程
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膜技术
✓ 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）