SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Hongbin Li,Hengji Liu,Wenying Shi,Haixia Zhang,Rong Zhou,Xiaohong Qin
Mixed matrix membranes (MMMs) combine the advantages of different materials and hopefully break through the limitation of high mass transfer resistance and low permeability in membrane distillation (MD) process. In this study, hydrophobic zeolitic imidazolate framework-71 (ZIF-71)/polyvinylidene fluoride (PVDF) hollow fiber composite membrane was prepared by the dilute solution coating method. ZIF-71 was incorporated into the PVDF dilute solution and a macroporous hydrophobic ZIF-71/PVDF coating layer was formed on the outer surface of PVDF hollow fiber support membrane through the nonsolvent induced phase separation (NIPS) process. PVDF hollow fiber support membrane was fabricated by the dry-jet wet spinning process. Membrane surface morphologies were observed through Field emission scanning electron microscope (FESEM). The effects of zeolitic imidazolate frameworks (ZIFs) content in PVDF coating layer on membrane surface hydrophobicity and desalination performance were investigated through Dynamic water contact angle (WCA) measurements and the vacuum membrane distillation (VMD) experiment, respectively. The VMD experiment was carried out at feed temperature 50 °C and permeation side vacuum 31.3 kPa using 3.5 wt% NaCl aqueous solution as the feed solution. Compared with the uncoated PVDF hollow fiber membrane, both the surface hydrophobicity and the water permeability of the ZIFs-incorporated PVDF hollow fiber composite membranes are improved. The surface WCA and permeation water flux of ZIFs-PVDF composite membrane increase from 94.5 to 136.5° and 13.5 to 27.1 kg . m −2. h −1 meanwhile the NaCl rejection could maintain at 99.99%. No obvious pore wetting phenomenon was observed for ZIFs-PVDF hollow fiber composite membrane during the continuous VMD experiment for 60 h. The dilute solution coating is a promising method to prepare high-performance hollow fiber composite membrane for the desalination in MD process.
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
AICHE JOURNAL
·
2023
·Vol. 70
·期 1
·e18239
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IF 3.7
Jianshuang Zhang,Jinglan Wu,Meizhen Gao,Lifang Ge,Mengyao Wang,Jinxiang Dong,Qi Shi
The bio-based diols 1,3-propanediol (1,3-PDO) and 2,3-butanediol (2,3-BDO) can form strong hydrogen bonds with water, which increases the separation difficulty of diols in aqueous solutions. Herein, a series of mixed-linker ZIF-71-clnIm x samples with hydrogen bond–van der Waals (vdW) dual recognition sites have been constructed using 4-chloro-5-nitroimidazole (clnIm) linkers to substitute partially for the original 4,5-dichloroimidazole (dclIm) linkers of the ZIF-71 framework. The experimental and calculated results show that ZIF-71-clnIm x with appropriate clnIm substitution proportion ( x = 7.6 and 12.8 mol%) can strengthen the interaction between ZIF-71-clnIm x and 2,3-BDO and enhance the adsorption and mass transfer of 2,3-BDO, thus achieving the efficient separation of 2,3-BDO/1,3-PDO. Molecular simulation results further verify that 2,3-BDO can simultaneously form strong H bonds with the –NO 2 of the clnIm linker and weak vdW interactions with the –Cl of the dclIm linker, which are the mixed recognition sites for 2,3-BDO adsorption intensification in aqueous solution for ZIF-71-clnIm x .
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
SOLID STATE IONICS
·
2020
·
IF 3.107
Ying Zhou,Tingting Zhou,Yipeng Zhang,Li Tang,Qing Guo,Mingfeng Wang,Changsheng Xie,Dawen Zeng
Core-shell heterostructures of metal oxide semiconductor (MOS) and metal organic framework (MOF) improve gas-sensing properties due to the MOF's molecular sieving effects. However, the selection of MOF is limited by the requirement of identical metal element in MOF to that in MOS, which is crucial for valid interface adhesion. In this paper, WO 3 @ZIF-71 (zeolitic imidazolate framework) structure with different metal elemental components (W and Zn) was fabricated by a step-by-step (SBS) approach. As a result, ZIF-71 was uniformly coated on the surface of WO 3 . In order to explore the influence of ZIF-71 (pore size: 4.8 Å), the gas sensitivity of WO 3 and WO 3 @ZIF-71 were tested. Different kinetic diameters gases: H 2 S (3.62 Å), CH 3 COCH 3 (4.6 Å), CH 3 CH 2 OH (4.53 Å), NO 2 (5.8 Å) were selected as testing gas. Gases with small molecules (H 2 S, CH 3 COCH 3 and CH 3 CH 2 OH) can pass through the membrane of ZIF-71 and contact with WO 3 , while larger ones (NO 2 ) were blocked outside the membrane. Excitingly, the response of WO 3 @ZIF-71 toward H 2 S gas was significantly improved, which soars from 2.24 of 20 ppm for pure WO 3 to 19.12 for H 2 S at 250 °C, increased about 9 times. These results indicate that the MOS@MOF core-shell structure can be synthesized by the SBS method without the restriction of the same metal elements in MOS and MOF, which is also an effective approach to regulate the selectivity and sensitivity of the MOS@MOF gas sensor.
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 Environmental Chemical Engineering
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2024
·
IF 7.4
Jin Wang,Longhui Fang,Yutao Ban,Xiangyang Liu,Maogang He
Due to their high global warming potential (GWP), hydrofluorocarbons (HFCs) are included in various regulations as substances to be phased down. Gas separation membrane technology is expected to provide a better choice for refrigerant separation. In this study, a series of metal-organic frameworks (MOFs)/ polydimethylsiloxane (PDMS) mixed matrix membranes (MMMs) were prepared for the separation of the refrigerant blend R454A (GWP = 145), which consists of a near-zeotropic difluoromethane (R32, GWP = 675) and 2,3,3,3-tetrafluoropropene (R1234yf, GWP = 4). ZIF-71-NH 2 was prepared for the first time by solvent-assisted ligand exchange (SALE), and then ZIF-71-NH 2 @ Ionic Liquid (IL) was prepared by embedding [C 2 mim][BF 4 ] into the pores of ZIF-71-NH 2 by capillary action method. The results showed that a hydrogen bonding network was established between the amino group and PDMS, which improved the interfacial compatibility, and reduced the pore size of ZIF-71, which contributed to an excellent gas separation performance of ZIF-71-NH 2 /PDMS MMMs. Restricting [C 2 mim][BF 4 ] to the ZIF-71-NH 2 pore can further reduce its pore size, and enhance R32/R1234yf separation performance due to the high selective solubility for R32 and R1234yf. The selectivity of 10 wt% ZIF-71-NH 2 /PDMS MMM is 25.6 % over that of 10 wt% ZIF-71/PDMS MMM. The selectivity of ZIF-71-NH 2 @IL/PDMS MMM is 38.3 % higher than that of ZIF-71-NH 2 /PDMS MMM. The ZIF-71-NH 2 /PDMS and ZIF-71-NH 2 @IL/PDMS MMMs exhibited the most excellent R32/R1234yf separation performance compared with the data currently published in the literature. Moreover, both designed MMMs demonstrated excellent resistance to ageing.
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
ACS Applied Nano Materials
·
2023
·
IF 5.9
Linlin Qian,Canxiang Fang,Yanghai Gui,Kuan Tian,Huishi Guo,Dongjie Guo,Xiang Guo,Peng Liu
NO2 is a very dangerous and toxic gas and is prone to cause acid rain in high humidity environments, so it is essential to prepare a real-time monitoring and humidity immunity NO2 sensor. WO3 nanomaterials are commonly applied to detect NO2, but their poor immunity to humidity is still a critical limitation for the application. ZnO-nanorod-decorated WO3 nanosheets coated with ZIF-71 (ZnO@ZIF-71/WO3) composites prepared by an in situ growth method displayed excellent gas sensing performance and good humidity immunity to detect NO2. Compared to WO3 nanosheets and ZnO-nanorod-decorated WO3 nanosheets (ZnO/WO3) heterojunction composites grown on ceramic substrates in situ, ZnO@ZIF-71/WO3 presented excellent selectivity, good long-term stability, and a remarkably high response of about 947.96 to 100 ppm NO2 at 180 °C, which is 3.07 times higher than that of the ZnO/WO3 sensor and 4.59 times higher than that of the pure WO3 sensor. Even at a relative humidity of 85%, the response of ZnO@ZIF-71/WO3 to NO2 remained essentially constant. The functional ZIF-71 layer not only improved the humidity immunity of ZnO@ZIF-71/WO3 but also enhanced the sensitivity and selectivity performance to NO2 at low operating temperatures. The ZnO@ZIF-71/WO3 sensor still provided a response of 88.41 to 100 ppm NO2 at room temperature.
研究领域:
材料科学
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环境科学
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化学工程
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产品关联
DOI
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
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2024
·
IF 6.9
Xiangyang Liu,Jin Wang,Longhui Fang,Yutao Ban,Maogang He
Due to the high Global Warming Potential (GWP) of hydrofluorocarbons (HFCs), the Kigali Amendment to the Montreal Protocol explicitly calls for the phase-out or limited use of HFCs, and the replacement of HFCs by hydrofluoroolefins (HFOs) is imminent. Therefore, it is particularly significant to develop new technology to separate valuable difluoromethane (R32, GWP = 675) from the near-azeotropic refrigerant blend R410A (GWP = 2088), because the traditional distillation is not applicable. In this work, aiming to enhance the separation performance of mixed matrix membrane (MMMs) for R410A, 5-fluorobenzimidazole was introduced into ZIF-71 by the solvent assisted linker exchange (SALE) method for the first time to reduce the pore size of fluorinated ZIF-71 by benzene rings and form hydrogen bonds between R32 with ZIF-71. A novel series of MMMs consisting of fluorinated ZIF-71 and Poly(ether-block-amide) ®1657 (Pebax®1657) polymer were prepared to separate the components of the R410A. The separation performance of the MMMs was investigated at different feed pressures and filler loading. The results showed that the introduction of 5-fluorobenzimidazole contributed to a significant increase in R32 permeability and R32/R125 selectivity of the MMMs compared to pure Pebax membrane. The 15 wt% ZIF-71-F/Pebax MMM showed the best separation performance with R32/R125 selectivity up to 26.6, four times that of pure Pebax membrane and twice that of ZIF-71/Pebax MMM. The ZIF-71-F/Pebax MMM have outstanding data on R32/R125 selectivity and no significant disadvantage in permeability, far exceeding the reported separation performance of membranes for R410A. This confirms that the application of fluorinated metal organic frameworks (MOFs) to the separation of refrigerant blends is a promising strategy.
研究领域:
材料科学
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环境科学
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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
·
IF 8.1
Zhongming Zhang,Enfang Gou,Zhiying Zhao,Rui Wu,Rui Fang,Weipeng Guo,Jie Yao
Organophilic pervaporation (PV) mixed matrix membranes (MMMs) have enormous potential for organic wastewater treatment due to their environmental friendliness and high efficiency. However, developing a high-flux PV membrane remains challenging. In this work, the nanocage-like hollow ZIF-71(h) (HZIF-71(h)) polyhedral nanocrystals were synthesized by heteroepitaxial growth of a ZIF-71(h) shell and successive excavation of a ZIF-67 core. The resultant HZIF-71(h) nanocrystals were blended with poly (ether block amide) (PEBA) matrix to fabricate MMMs for phenol/water separation. Results from several characterization techniques confirmed the successful preparation and formation mechanism of HZIF-71(h). Further, a series of experiments were conducted using the composite membranes to explore the impact of filler type, filler loading, operating temperature, and feed concentration on the separation performance. The incorporation of ZIFs facilitated phenol permeation while limited water transport, thereby resulting in increased separation factor. Notably, the HZIF-71(h)/PEBA-21 MMM exhibits a higher phenol flux in comparison to ZIF-71/PEBA-21 and ZIF-67/PEBA-21 MMMs, indicating the importance of the low-resistance hollow structure. The HZIF-71(h)/PEBA-21 MMM exhibits outstanding pervaporation performance with a separation factor of 15.86 and a phenol flux of 17.32 g·m −2 ·h −1 , respectively, displaying an improvement of 41.2 % and 6.4 % compared to the PEBA/PVDF membrane. Furthermore, this composite membrane demonstrated outstanding durability during continuous testing for 84 h, implying a promising potential for phenol 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
SENSORS AND ACTUATORS B-CHEMICAL
·
2025
·
IF 7.7
Longyu Ren,Yuhang Du,Ya Wang,Jinan Li,Ruojin Zhang,Jiliang Yuan,Hongyan Xu
In 2 O 3 , as a traditional metal oxide semiconductor substrate material, responds to various toxic and harmful gases but with poor selectivity. This paper uses the hydrothermal method to grow dense and uniform In 2 O 3 nanorods vertically on a ceramic tube, and then covers them with ZIF-71. By adjusting the type of solvent used to synthesize ZIF-71, the morphology and properties of the material can be changed. The pores and large specific surface area of ZIF-71 are utilized to sieve large molecular gases, providing more adsorption sites for NO 2 gas. And it forms heterostructure with In 2 O 3 to enhance the response to NO 2 . The optimized gas sensor In 2 O 3 @ZIF-71(CH 3 OH) shows superior response (185, S=R g / R a ) and selectivity of 50 ppm triethylamine as an interfering gas (7.23, S=R a / R g ) to 50 ppm NO 2 compared to pure In 2 O 3 nanorods. Molecular dynamics simulation is used to study the gas adsorption performance of ZIF-71 and theoretical simulation of the adsorption behavior of NO 2 on the In 2 O 3 substrate is conducted through density functional theory. The simulation results show that the ZIF-71 molecular sieve can reduce the response to large molecule TEA gas through the dual effects of pore size adsorption and blocking, thereby improving the selectivity of the material. Indium oxide (In 2 O 3 ) has an adsorption effect on nitrogen dioxide (NO 2 ), with an adsorption heat of 0.499 electron volts, and its adsorption effect is relatively stable.
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产品关联
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Zhongming Zhang,Yijun Liu,Zhengda Lin,Rui Wu,Rui Fang,Weipeng Guo,Jie Yao
Given the increasing concerns for both the environment and human health, the treatment of wastewater containing phenolics has emerged as a pressing yet daunting matter. In this work, the mixed matrix membranes (MMMs) with exceptional performance have been created by introducing controllable morphology and structure zeolitic imidazolate framework-71s (ZIF-71s) into polyether block amide (PEBA) matrix for the purpose of phenol-water separation. The impacts of ZIF-71s dimension and ZIF-71s loading amount on the separation performance were comprehensively analyzed, as well as operational temperature and operational concentration on the separation performance. The crystal transformation of three-dimensional ZIF-71K nanoparticles into two-dimensional ZIF-71P nanosheets was accomplished by altering the modulators in aqueous system. The presence of ZIF-71s could lead to a decrease in water flux, while the phenol permeation flux was essentially unaffected. The filling of two-dimensional ZIF-71P nanosheets established a classic “brick-and-mortar” structure within the polymeric bulk, which resulted in the enhancement of tortuous pathways and energy barriers for water penetration, hence further boosted the membrane selectivity. For an operating temperature of 50 °C and a phenol concentration of 1000 ppm, the ZIF-71P/PEBA-21 MMMs exhibited separation performance with total permeate flux and separation factor of 911.10 g·m −2 ·h −1 and 18.96, while the ZIF-71K/PEBA-21 membrane demonstrated total permeate flux and separation factor of 965.49 g·m −2 ·h −1 and 17.74. And the MMMs presented a superior separation performance in comparison with the PEBA/PVDF membrane. On top of that, the resultant MMMs also demonstrated promising long-term stability as phenol enrichment methods, which holds significant promise for implementation in the recovery of phenol from relevant industrial wastewater.
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
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 22
·18052-18059
·
IF 3.289
Yi-Hua Wang,Qi Shi,Hong Xu,Jin-Xiang Dong
Small- and large-sized crystalline ZIF-71 was synthesized using different strategies and has average diameters of approximately 450 nm, and 1–2 μm. Large-sized ZIF-71 particles with good crystallinity were prepared by a solvothermal synthesis method and small-sized ZIF-71 particles were prepared upon the addition of an acidic additive (formic acid) at room temperature. The two different sizes of particles were used as oil additives in liquid paraffin, and investigated using four-ball tribotesters. The results show that the small-sized particles can improve the anti-wear properties and load-carrying abilities of the base oil. The large-sized particles exhibit good load-carrying capacity. Wear surfaces were analysed by using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and Zygo Zegage 3D optical profiler after the wear tests.
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
Advanced Healthcare Materials
·
2023
·
IF 10
Lei Chen,Xiaomei Wang,Mengping Chen,Qiwen Sun,Yemeng Chen,Xiaojie Zhang,Rui Hong,Yigong Xu,Jingwen Guan,Sheng Hong,Dehan Cao,Tingfeng Sun,Ximeng Li,Lanhua Chen,Juan Diwu
The limited availability of effective agents for removing actinides from the lungs significantly restricts the effectiveness of medical treatments for nuclear emergencies. Inhalation is the primary route of internal contamination in 44.3% of actinide-related accidents, leading to the accumulation of radionuclides in the lungs and resulting in infections and potential tumor formation (tumorigenesis). This study focuses on the synthesis of a nanometal−organic framework (nMOF) material called ZIF-71-COOH, which is achieved by post-synthetic carboxyl functionalization of ZIF-71. The material demonstrates high and selective adsorption of uranyl, while also exhibiting increased particle size (≈2100 nm) when it aggregates in the blood, enabling passive targeting of the lungs through mechanical filtration. This unique property facilitates the rapid enrichment and selective recognition of uranyl, making nano ZIF-71-COOH highly effective in removing uranyl from the lungs. The findings of this study highlight the potential of self-aggregated nMOFs as a promising drug delivery system for targeted uranium decorporation in the lungs.
研究领域:
放射医学
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材料科学
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纳米技术
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
·
2019
·Vol. 28
·期 3
·1668-1677
·
IF 1.476
Yuan Min,Zhao Yu,Niu Wenxing,Shi Qi,Xu Hong,Zheng Bin,Dong Jinxiang
In this study, three different zeolitic imidazolate framework (ZIF) materials of ZIF-8, ZIF-71, and MAF-6 were synthesized, and their tribological properties as base grease were evaluated. We demonstrate that the tribological properties of ZIFs are correlated with the framework density/pore volume and the substituted groups. Under 200 N, MAF-6 has the lowest wear volume value and ZIF-71 exhibits the lowest friction coefficient. As the load increased, MAF-6 maintained the best and most stable tribological performances among the three ZIFs additives; however, the properties of ZIF-71 worsened. Thus, MAF-6 exhibits the lowest density and largest solvent-accessible volume (SAV) and has the lowest elastic stiffness; it easily slides and adheres onto the wear surface, forming a tribofilm that reduces friction and prevents severe wear. ZIF-71 with chlorinated groups may enhance the tribological performance; as the load rises, its dense and stiff structure has an adverse effect. These results are expected to be helpful for designing future ZIFs with excellent lubrication properties.
研究领域:
材料科学
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机械工程
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DOI
高影响因子
危险品化学品经营许可证（带存储）