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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DOI
高影响因子
NANOTECHNOLOGY
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2021
·Vol. 32
·期 47
·475708
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IF 3.874
Qiu-Ping He,Yun Zou,Peng-Fei Wang,Xiao-ming Dou
Silicalite-1 zeolitic membranes have been successfully fabricated on the porous α-Al2O3 support by templated and template-free protocol, respectively, for vapor permeation separation of dichlorobenzene (DCB) isomers. After proving the high quality of the membranes by single gas permeation (He and SF6) performance, the vapor-permeation of DCB isomers over two types of the silicalite-1 membrane was then investigated. The separation results clearly indicated that under the lower partial pressure and higher temperature, the effect of DCB isomer adsorption on the permeance could be kept at a sufficiently low level and sharp selectivity become more important. Thus, high p-DCB selectivity could be achieved. Comparatively, the template-free silicalite-1 zeolite has a much higher p-DCB selectivity due to the relatively fewer inter-crystalline gaps. Under certain separation conditions, the highest selectivity of p-DCB for p-/m-DCB and p-/o-DCB binary systems could reach 165 and 113, respectively.
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
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2026
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IF 3.5
Yulong Li,Chao Fan,Penghui Ren,Yongming Gu,Jia Ding,Jiaxing Hu,Jianguo Wang
Catalyst-membrane coupling reactor (CMCR) was fabricated for enhancing amino acid esterification. • In situ water separation was achieved by a PVA/Al 2 O 3 hollow fiber membrane. • HCl promoted the vapor permeation performance of the PVA/Al 2 O 3 membrane. • The HND-2 solid acid resin catalyst and PVA/Al 2 O 3 membrane exhibited excellent reusability. • CMCR also demonstrated good universality for various amino acid esterifications. . Amino acid ester hydrochlorides are critical intermediates used to produce pharmaceuticals and fine chemicals. The synthesis of amino acid ester hydrochlorides industrially adopted thionyl chloride (SOCl 2 )-mediated route, from which substantial SO 2 is generated and poses a great threat to the environment. In this study, a SOCl 2 -free catalyst-membrane coupling reactor (CMCR) was fabricated for amino acid esterification, which integrated HND-2 solid acid resin catalyst and polyvinyl alcohol (PVA) membrane supported on a four-channel α-Al 2 O 3 hollow fiber. Karl Fischer titration directly confirmed the effective water removal ability of the PVA/Al 2 O 3 membrane. In the esterification of DL-serine with methanol, the CMCR achieved a DL-serine conversion of 93.1%, outperforming the traditional reactor without membrane (86.5%). In addition, it was found that HCl dissolved in methanol improved the solubility and conversion of DL-serine. More importantly, vapor permeation experiments and simulation calculations indicated that HCl resulted in a 3.3-fold increase in water flux and ∼83.7% improvement in H 2 O/MeOH separation factor by promoting the water vaporization. The CMCR also demonstrated excellent reusability and universality for the esterification of other amino acids with alcohols. This work proposes a green and efficient reaction-separation coupling strategy for the synthesis of amino acid ester hydrochlorides, providing a viable alternative to replace the SOCl 2 -mediated route. Researchers have developed a reaction-separation coupling system that intensifies the esterification of serine with methanol to produce serine methyl ester hydrochloride, via the synergistic coupling of solid acid HND-2 and a PVA/Al 2 O 3 dehydration membrane. This system efficiently separates water generated during the esterification reaction, overcomes the thermodynamic equilibrium constraints, and significantly enhances the conversion efficiency of the reactants. Furthermore, this study reveals that hydrogen chloride can effectively facilitate the separation of water throughout the reaction process. Collectively, this work affords a novel strategy for the green synthesis of amino acid esters in industrial production. Download: Download high-res image (213KB) Download: Download full-size image
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高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2017
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IF 6.035
Jiajun Fan,Wei Zhou,Qing Wang,Zhaojie Chu,Lanqiong Yang,Lei Yang,Jian Sun,Ling Zhao,Jianmei Xu,Yujun Liang,Zhiquan Chen
Incorporation of nanoplatelets is known to be effectively in the reduction of gas permeation of polymer membranes, which has been typically attributed to the torturous path effect. However, the measured water vapor transmission rates (WVTR) from the poly(vinyl alcohol) (PVA)/graphene oxide (GO) nanocomposite membranes are found to be smaller than the theoretical values calculated by the Bharadwaj model based on the torturous path effect. This discrepancy is indicative of the existence of other structural factors responsible for the WVTR that are rarely discussed in literature. In this work, the positron annihilation lifetime spectroscopy (PALS), a widely recognized method for characterization of the atomic-scale microstructure of polymers, is employed herein to study the free volume of the PVA/GO composite membranes . The free volume size of the composite membrane decreases with increasing GO contents, and the fractional free volume (FFV) decreases with the increase of annealing temperature. Strong dependence of the WVTR of PVA/GO on the FFV and crystallinity has been revealed, indicating that, along with the nanoplatelets-induced torturous path effect, they are important factors affecting the water vapor permeation of polymer nanocomposite membranes.
研究领域:
材料科学
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聚合物科学
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高影响因子
CHEMICAL ENGINEERING SCIENCE
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2019
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IF 3.372
Pei-Yao Zheng,Wen-Hai Zhang,Chong Li,Nai-Xin Wang,Jie Li,Zhen-Ping Qin,Quan-Fu An
Vapor permeation seems to be a more suitable separation process than pervaporation in bio-ethanol recovery from fermentation broth because of its non-direct contact trait. The unsatisfactory flux and selectivity of polymeric membranes limit their utilization in industrial application. Here, we tailored the physical and chemical structure of commercial available polyacrylonitrile (PAN) ultrafiltration membrane to serve in vapor permeation. The membrane porosity was reduced till dense enough for separation while preserving an ultra-high flux by hydrolyzing in alkali. The hydrophilicity/hydrophobicity was controlled by grafting fluoroalkyl chains to ensure an acceptable ethanol selectivity. The changes of physical structure and chemical property were systematically characterized by Fourier transform infrared-attenuated total reflectance (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), water contact angle and pure water permeance. Tested at 60 °C, the optimized membrane exhibited a high flux of ca. 10.5 kg m −2 h −1 and a permeate ethanol content similar to vapor-liquid equilibrium curve, which outstripped most polymeric membranes (applied in pervaporation or vapor permeation) in both flux and selectivity.
研究领域:
生物工程
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化学工程
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DOI
高影响因子
危险品化学品经营许可证（带存储）