JOURNAL OF MEMBRANE SCIENCE
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2024
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IF 8.4
Zhigang Xue,Yuan Shen,Liang Chen,Bo Liu,Na Hu,Rongfei Zhou,Weihong Xing
Pervaporation (PV) and vapor permeation (VP) using selective zeolite membranes are more energy-saving in dealing with azeotropic mixtures compared with conventional distillation for organic solvent dehydration. Herein, we developed a monolithic supported chabazite membrane and exploited its dehydration performance. The membrane was fabricated by secondary growth method on the 19-channel alumina monolithic without organic template. By finely controlling the homogeneity of nuclei growth and minimizing the intracrystalline defects through the epitaxial growth of uniformly nanosized SSZ-13 seed layer using cesium hydroxide and sodium hydroxide as cooperative hydration-mismatched inorganic structure directing agents (ISDA). The resulting monolithic chabazite membrane exhibits excellent water-perm-selectivity. The effects of feed water composition and operating temperature on the dehydration performance of the monolithic chabazite membrane were investigated through PV and VP processes. The typical membrane displayed excellent selectivities of more than 10,000 and 30,000 in 10/90 wt% water/ethanol and water/isopropanol mixtures at 393 K. The membrane exhibited excellent hydrothermal stability in a VP with a 10/90 wt% water/ethanol at 393 K for 72 h. The robust monolithic chabazite membrane with high packing density, strong mechanical strength, large membrane area and excellent water-selective performance significantly outperforms state-of-the-art membranes for dehydration in practical applications.
研究领域:
化学工程
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材料科学
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产品关联
DOI
高影响因子
Frontiers of Chemical Science and Engineering
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2020
·Vol. 15
·期 4
·882-891
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IF 3.552
Fan Yiyi,Li Jinyong,Wang Saidi,Meng Xiuxia,Jin Yun,Yang Naitao,Meng Bo,Li Jiaquan,Liu Shaomin
Hydrogen fuel has been embraced as a potential long-term solution to the growing demand for clean energy. A membrane-assisted separation is promising in producing high-purity H 2 . Molecular sieving membranes (MSMs) are endowed with high gas selectivity and permeability because their well-defined micropores can facilitate molecular exclusion, diffusion, and adsorption. In this work, MXene nanosheets intercalated with Ni 2+ were assembled to form an MSM supported on Al 2 O 3 hollow fiber via a vacuum-assisted filtration and drying process. The prepared membranes showed excellent H 2 /CO 2 mixture separation performance at room temperature. Separation factor reached 615 with a hydrogen permeance of 8.35 × 10 −8 mol·m −2 ·s −1 ·Pa −1 . Compared with the original Ti 3 C 2 T x /Al 2 O 3 hollow fiber membranes, the permeation of hydrogen through the Ni 2+ -Ti 3 C 2 T x /Al 2 O 3 membrane was considerably increased, stemming from the strong interaction between the negatively charged MXene nanosheets and Ni 2+ . The interlayer spacing of MSMs was tuned by Ni 2+ . During 200-hour testing, the resultant membrane maintained an excellent gas separation without any substantial performance decline. Our results indicate that the Ni 2+ tailored Ti 3 C 2 T x /Al 2 O 3 hollow fiber membranes can inspire promising industrial applications.
研究领域:
材料科学
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能源工程
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2023
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IF 8.6
Yang Jiao,Qi Wu,Wei Xu,Wei Lai,Luqi Xiao,Xue Mei,Hongjun Zhang,Shuangjiang Luo
Tailoring the microporous architecture of the precursors facilitates the gas separation performance in carbon molecular sieve (CMS) membranes. Herein, we report a facile strategy to tune the gas separation performance of CMS membranes through coordination between rare earth and imidazoles in the hierarchical triptycene-based polybenzimidazole (TPBI) precursor. By optimizing the pyrolysis condition and rare earth doping level, the resulting CMS membranes exhibited unprecedented H 2 and He permeabilities and high gas selectivities, and the TPBI-Yb 0.67 @700 CMS membrane exhibited a 3-fold increase in H 2 permeability and a 2-fold increase in H 2 /CO 2 selectivity compared to the TPBI-CMS@700 CMS membrane. It was demonstrated by the solution/diffusion coefficients and microporosity analysis that the enhancement of gas separation performance originated from the more pronounced hierarchically slit-like micropore structure, as well as the boosted diffusion and sorption selectivities. The TPBI-Yb 0.67 @700 membrane displayed a H 2 permeability of 8648 Barrer and a mixed-gas H 2 /CO 2 selectivity of 14.5 at 150 °C, far exceeding the experimental CMS upper bound.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2025
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IF 9
Shenghan Ji,Ziheng Li,Yan Dai,Xiaobin Jiang,Xuehua Ruan,Wenji Zheng,Gaohong He
MOF membrane supported on flexible substrates faces the issues of non-selective defects as well as poor mechanical compatibility. Herein, a “rigid and flexible” MOF/COF molecular sieving membrane is acquired by the in-situ polymerization of COFs among the inter-crystalline and interfacial defects in the MOF membrane. Taking advantage of different osmotic pressures on both sides of MOF membrane during the counter-diffusion process, the COFs monomers diffuse from bottom to top to the inter-crystalline and interfacial defects and meet with the catalyst for further polymerization and crystallization, thus repairing non-selective defects of the MOF membrane. In the MOF/COF membrane, COFs exhibit a strong adsorption affinity for CO 2 , which can slow down CO 2 permeation and enhance H 2 /CO 2 selectivity. Meanwhile, the in-situ polymerization of COFs primarily occurs at the inter-crystalline defects of MOF membrane and the interface between MOF membrane and polymer substrate, without forming a resistance layer on MOF membrane surface, which is demonstrated by the SEM and AFM results. Additionally, the counter-diffusion growth of COFs allows for the connection between the organic substrate and the inorganic MOFs layer through COFs, thereby improving the mechanical flexibility of MOF membrane confirmed by the mechanical properties. Besides, through regulating the polymerization process of TpPa-1 including time and monomer concentration, the H 2 /CO 2 separation of ZIF-67/TpPa-1 membrane can be tuned precisely. Therefore, the ZIF-67/TpPa-1–0.90 membrane at a polymerization time of 24 h presents H 2 permeance of 1114 GPU and H 2 /CO 2 selectivity of 17.52, an increase of 178.1 % compared to the pure ZIF-67 membrane, which is far beyond the 2008 upper bound and approaching the up-to-date data line. Together with the additional good mechanical properties, stability and universality, the proposed “rigid and flexible” MOF/COF molecular sieving membrane is promising in H 2 /CO 2 separation.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
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IF 8.1
Bingyu Zhao,Haojie Li,Zian Chen,Jiawei Lin,Yaodong Liu
The potential of carbon molecular sieve membranes (CMSM) for gas separation is widely recognized, and the key precursor for these membranes is polyimide (PI). This study focuses on enhancing the gas separation properties of CMSMs by introducing a unique structural element, Tröger’s bases, into polyimides, resulting in the creation of five distinct polyimides containing Tröger’s bases (PI-TBs). The incorporation of Tröger’s bases has a profound impact on the arrangement of polymer chains within the PIs, leading to a substantial improvement in gas permeability without compromising selectivity. Following carbonization at 600 °C, the resultant CMSMs exhibit significantly enhanced gas permeability while preserving, and in some cases, improving gas selectivity. Among the various types of diamines considered, the 6FDA variant of PI-TB stands out, boasting outstanding gas permeability with a H 2 permeability of 4991.0 Barrer and a H 2 /CH 4 selectivity of 30.7; this level of performance surpasses the 2015 Robeson’s upper bound. Furthermore, thermal analysis coupled with mass spectrometry (TG-MS) reveals that the pyrolysis of Tröger’s bases commences prior to that of polyimide . This sequential degradation process facilitates the formation of pyridine N and promotes the π-stacking of PI chains; both of which are instrumental in maintaining excellent gas selectivity. These findings provide valuable insights into the roles of Tröger’s bases in enhancing the gas separation performance of PIs and CMSMs, offering a promising avenue for further advancements.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
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IF 8.1
Li Peng,Zhaofeng Duan,Shumin Cen,Xuehong Gu
High-silica CHA (SSZ-13) zeolites membranes, with pore size between the molecular size of CO 2 and N 2 or CH 4 , are promising for some industrial CO 2 separation process. Considering water is typically present in these industrial gas feed and the negative impact of moisture on the membranes’ gas permeation, it is highly desirable to increase the surface hydrophobicity of membranes to reduce the adsorption of water. In this paper, a W-doping strategy was proposed to increase the hydrophobicity of SSZ-13 membranes by eliminating the silanols on the surface, and the W-doped high-silica CHA (W-SSZ-13) zeolite membranes were prepared for the first time. Characterizations such as SEM, XRD, and XPS confirmed the successful incorporation of W into CHA membrane. The incorporation of W reduced the pore mouth size, and the W-SSZ-13 zeolite membranes showed improved CO 2 /N 2 and CO 2 /CH 4 separation performance. After W-doping, the maximum separation factors ( α max ) for the CO 2 /N 2 mixture with equimolar composition under dry conditions increased from 8.8 to 16.9, and for the equimolar CO 2 /CH 4 mixture, the value increased from 105.9 to 176. The W-SSZ-13 membranes also showed better separation performance under wet conditions. For both systems, the W-SSZ-13 membrane showed higher α max and less CO 2 permeance reductions, indicating a more resistance in wet conditions.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2019
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IF 7.015
Xiansong Shi,Ankang Xiao,Chenxu Zhang,Yong Wang
Crystalline imine-based covalent organic frameworks (COFs) have attracted great interest as next-generation water treatment materials owning to their numerous merits. The construction of COF layers with tunable pore sizes ranging from meso- to micropores, which can significantly broaden the membrane selectivity from ultra- (UF) to nanofiltration (NF), has remained unexplored. Herein, we demonstrate the controllable solvothermal synthesis of COF layers with adjustable pore sizes on anodic aluminum oxide (AAO) substrates. With rising synthesis duration the modulation on pore sizes of AAO supports can be achieved till the formation of continuous COF layers, leading to a gradually enhanced selectivity. Importantly, the synthesized microporous COFs shrink the pore sizes of AAO substrates and provide additional nanochannels for water transporting, eventuating in a ~2–9 times higher permeance than other reported UF membranes with comparable rejections. Once forming continuous COF layers, more rigid selectivities based on COF inherent nanochannels (~1.83 nm) can be realized with capacities of removing dyes from water or organic solvent . This work provides a facile methodology to construct COF-based membranes with broadly tunable separation performance, recommending the membranes for removing targeted molecules including proteins, nanoparticles , and dyes.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2024
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IF 8.4
Tao Zhou,Mingyu Zhu,Yong Dai,Lingjie Chen,Junyan Xie,Yuting Zhang,Xuerui Wang,Xuehong Gu
STT zeolite membrane with seven-membered rings (7 MR) and nine-membered rings (9 MR) is an ideal alternative for the separation of hydrogen (H 2 ) and methane (CH 4 ). However, the successful synthesis is only possible in rotation conditions, which is difficult to achieve at an industrial scale. Herein we developed a static synthesis approach to prepare high-quality STT zeolite membranes. The precursor transformed in-situ from a liquid state to a semi-solid state to efficiently suppress the nucleation in the bulk gel. This did not affect the growth of the seed layer to form a continuous membrane. The water content was modulated between y = 44 and y = 124 in the molar composition of 1 SiO 2 : 0.2 TMAdaOH: y H 2 O. The precursor could be re-used one more time to reduce the total amount of chemical waste. The optimal H 2 permeance and H 2 /CH 4 mixture selectivity was up to 6.1 × 10 −8 mol m −2 s −1 Pa −1 and 115 at atm pressure. The H 2 permeation flux monotonically increased to 2.0 Nm 3 m −2 h −1 under feed pressure up to 2.1 MPa. This paves the way for zeolite membranes to high-pressure H 2 separation in practical applications.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
CHEMOSPHERE
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2024
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IF 8.1
Jian Liu,Xueren Huang,Zhengji Yi
Complexing agents (CAs) can be used for the removal of Cr(VI) via nanoscale Fe 0 (nZVI) reduction in cost-effective manner. However, nZVI is prone to aggregation and passivation, and some conventional CAs are toxic and difficult to biodegrade, potentially causing secondary pollution. Therefore, selecting an environmentally friendly CA for assisting in the removal of Cr(VI) via supported nZVI is imperative. Herein, NaA molecular sieve membrane-supported nZVI (nZVI/NaA-NF) was prepared via the secondary growth and liquid-phase reduction method using nickel foam (NF) as the carrier. The physicochemical characteristics of nZVI/NaA-NF before and after reaction were analysed via SEM, EDS, and XPS. A CA-improved nZVI/NaA-NF was used for the effective removal of Cr(VI) in a continuous fixed-bed system. Furthermore, the influences of various experimental factors including the CA type, CA concentration, solution pH, space velocity, and inlet Cr(VI) concentration on Cr(VI) removal were systematically investigated. The results demonstrated that nZVI particles were homogeneously immobilized on the NaA molecular sieve membrane/NF for fresh nZVI/NaA-NF, and tetrasodium iminidisuccinate (IDS-4Na) inhibited the aggregation of Cr(III)/Fe(III) (hydr)oxide precipitates during the reaction. IDS-4Na demonstrated excellent promotive effect on Cr(VI) removal via nZVI/NaA-NF. The breakthrough time for Cr(VI) in the addition of IDS-4Na was considerably longer than that of nZVI/NaA-NF alone. The breakthrough concentration of Cr(VI) only reached 1.1% and 9.9% of the inlet concentration at 220 and 240 min, with an IDS-4Na concentration of 4 mM, a pH of 2.5, and a space velocity of 0.265 min −1 . The Bohart–Adams model was appropriate to predict the initial part of Cr(VI) breakthrough curves in the nZVI/NaA-NF fixed bed. The saturated concentration ( N 0 ) increased with an increase in inlet Cr(VI) concentration. The Yoon–Nelson model afforded good fitting results for all breakthrough curves of Cr(VI). The k′ value increased with an increase in space velocity, and the τ value decreased.
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
Membranes
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2021
·Vol. 11
·期 8
·618
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IF 4.106
Haojie Li,Shan Xu,Bingyu Zhao,Yuxiu Yu,Yaodong Liu
Blending and heat-treatment play significant roles in adjusting gas separation performances of membranes, especially for incorporating thermally labile polymers into carbon molecular sieve membranes (CMSMs). In this work, cellulose acetate (CA) is introduced into polyimide (PI) as a sacrificial phase to adjust the structure and gas separation performance from polymer to carbon. A novel result is observed that the gas permeability is reduced, even when the immiscible CA phase decomposes and forms pores after heat treatment at 350 °C. After carbonization at 600 °C, the miscible CA has changed without contribution, while the role of the immiscible CA phase has changed from original hindrance to facilitation, the composite-based CMSM at a CA content of 10 wt.% shows highest performances, a H2permeability of ~5300 Barrer (56% enhancement) with a similar H2/N2permselectivity of 42. The structural analyses reveal that the chain interactions and phase separation behaviors between CA and PI play critical roles on membrane structures and gas diffusion, and the corresponding phase structural evolutions during heat treatment and carbonization determine gas separation properties.Keywords:cellulose acetate;polyimide;chase separation behavior;carbon molecular sieve membranes
研究领域:
材料科学
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膜分离技术
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2022
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IF 10.53
Li Peng,Zhengqi Wu,Boxuan Wang,Hua Liu,Chun Zhang,Xuehong Gu
Pure silica MFI (Si-MFI) zeolite membranes with desirable hydrophobicity have the potential to separate ethanol/water mixture. However, its separation performance would significantly decrease in the long-term operation due to the presence of silanol groups formed in alkaline media. In this work, silanol-free MFI zeolite membranes were prepared by the incorporation of tungsten in MFI framework. The occurrence of silanol group can be prevented by formation of W–O–Si bridges. The synthesis parameters affected the W-MFI zeolite membranes’ microstructure and separation performance. For 5 wt% ethanol solution, the W-MFI zeolite membranes prepared at optimum condition showed stable separation performance of permeation flux as 2.81 kg m −2 h −1 with separation factor as 32 over 80 h at 60 °C. The membrane was characterized by XRD , DR UV–vis, XPS and 29 Si NMR, and the results confirmed the incorporation of W and the absence of silanol groups. This research showed that W-MFI zeolite membranes are promising candidates for ethanol extraction with high stability.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2020
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IF 7.183
Eryue Song,Kaifeng Wei,Haiqian Lian,Jingxian Hua,Hongxu Tao,Tingting Wu,Yichang Pan,Weihong Xing
Metal-organic frameworks (MOFs) used as molecular sieve membranes materials to gas separation has attracted much attention. However, the separation performance was also limited by its intrinsic flexibility of frameworks. Controlling its flexibility is still a big challenge. Herein, the doping of 2-aminobenzimidazole (ambz) into the ZIF-8 framework can obviously improve its original rigidity, which is due to the improved rigidity of the Zn‒N bond. Correspondingly, the high-quality doped ZIF-8 membrane for effective separation of C 3 H 6 /C 3 H 8 mixture were also fabricated. Compared with the permeation results on pure ZIF-8 membranes, the ambz-doped ZIF-8 membrane exhibited two specific transportation performance improvements. The first was that drop extent of C 3 H 6 /C 3 H 8 selectivity on the doped ZIF-8 membrane with the increase in feeding pressure was decreased, and the selectivity was also irreversible as the feeding pressure was released. This phenomenon was attributed to improved rigidity of the framework. The second was that the C 3 H 6 permeance was almost independent on the permeating temperature, which was also totally different with that on the pure ZIF-8 membrane, resulting from the significant change of adsorptive heat and diffusion energy of propylene on the ambz-doped ZIF-8 membrane. Therefore, this ambz-doped ZIF-8 membrane is promising in real world C 3 H 6 /C 3 H 8 separation.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
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