MICROPOROUS AND MESOPOROUS MATERIALS
·
2024
·
IF 4.8
Xue-Ling Wei,Jun-Bin Zhang,Wen-Yan Pan,Bo Song,Yu-Ling Luo,Qiang Liu,Zhi-Sheng Shi,Xingyang Li,ZongCheng Miao
Zeolite membranes have excellent application prospects in the separation of mixtures with molecular-level differences; however, the uneven distribution of active ingredients on the support causes defects in the zeolite membranes, limiting their industrial applications. In this study, compact NaX and NaA zeolite membranes with perfect pervaporation performance were prepared in reusable saturated membrane synthesis solutions. These saturated membrane synthesis solutions not only provided sufficient Si/Al components for the even growth of zeolite on the support, but also reduced the random deposition of zeolite particles on the support by reducing the formation of zeolite particles in the bulk solution, improving the quality of the resulting zeolite membranes. The separation factors of the obtained NaA and NaX zeolite membranes were greater than 10000 for the water/ethanol and methanol/MTBE mixtures, respectively. Moreover, the saturated synthesis solutions could be reused multiple times to synthesize zeolite membranes after nutrient supplementation, saving resources and reducing environmental pollution. This study presents reusable solutions for synthesizing compact zeolite membranes, promoting the development of membrane technology for environmental protection and energy conservation.
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
Xiaowei Wu,Yuqin Li,Yu Li,Mingyu Peng,Zhengquan Yang,Tian Gui,Xiangshu Chen,Hidetoshi Kita
Highly hydrophilic and durable Beta zeolite membranes with high aluminum (Al) spatial distribution were synthesized on inexpensive α-alumina supports via an organic template-free synthesis gel. In the absence of organic templates, the Al spatial distribution of Beta zeolite membrane crystal was regulated by the synthesis parameters such as the Al 2 O 3 /SiO 2 ratio, alkalinity, H 2 O/SiO 2 ratio and crystallization temperature, and the crystal morphology, Si/Al ratio and dehydration performance of the membrane could be further effectively controlled. Under optimal synthesis conditions, the prepared Beta zeolite membrane had an excellent separation factor of over 22,000 and a high permeation flux of 3.02 kg m −2 h −1 in the case of a 90 wt% n-butanol/water mixture at 75 °C. The high-performance Beta zeolite membrane was applied for continuous dehydration to obtain anhydrous n-butanol (99.9 wt%) from a 90 wt% n-butanol/water mixture. Furthermore, Beta zeolite membranes showed long-term acid stability in pervaporation dehydration of a 90 wt% n-butanol/water mixture with a pH value of approximately 2.0 at 75 °C for 192 h, indicating that these membranes by adjusting Al spatial distribution exhibited excellent hydrophilicity and acid resistance, which had a broad promising prospect of industrial applications for dehydration separation of acid-containing organic solvents.
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
SURFACE ENGINEERING
·
2020
·
IF 2.433
Jun Xing,Yingjie Chen,Chen-yun Yu,Ming-an Chen
For micro-arc oxidation (MAO) coating on aluminium alloys, the corrosion medium can permeate through the microvoids and cracks in it to decrease its corrosion resistance. In this study, a method of two-steps hydrothermal synthesis has been developed to prepare a composite coating by the synthesis of zeolite film on MAO-coated Al alloy substrate. The zeolite crystals are well intergrown into a continuous film and the micro defects in the MAO coating are sealed. This kind of composite coating can provide excellent long-term corrosion protection to Al alloy substrate. The effect of the first-step hydrothermal synthesis on the microstructure of the MAO coating and zeolite film has been studied.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Li Cao,Jun Zhou,Hong Hao,Prabir K. Dutta
Two types of zeolite meshes were examined in this study for oil/water separation. The first type involved nanozeolite seeds deposited uniformly on a stainless steel mesh. Second, secondary grown zeolite membranes were synthesized on stainless steel meshes. Both the zeolite meshes were found to be superamphiphilic and underwater superoleophobic. The oil/water separation properties of zeolite membrane meshes were investigated using different types of oil. It was found that the separation efficiency of the mesh was above 99.98%, with the residual rate of oil in water being less than 20 ppm. However, the seed layer mesh did not exhibit good repeatability. Secondary grown zeolite mesh exhibited no significant decline after 50 experiments with diesel and 30 trials with rapeseed oil. The secondary grown zeolite mesh has an average filtration flux of 37.68 m 3 /(m 2 ·h) under gravity. Furthermore, even after storage for two years, the oil/water separation performance of the secondary grown sample was maintained. The study concludes that the secondary grown zeolite membrane mesh has great potential in oil/water separation 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
FUEL
·
2025
·
IF 7.5
Xiaowei Wu,Yuqin Li,Zhengquan Yang,Mingyu Peng,Tian Gui,Xiangshu Chen,Hidetoshi Kita
A beta zeolite membrane reactor was first applied to improve conversion on the esterification of oleic acid and n-butanol at low temperature by rapidly removing the by-product water. In the pervaporation (PV)-esterification at low temperature of 353 K, the final conversion of oleic acid was significantly improved to 99.2 % in a short reaction time of 4 h. Even at an incredibly low esterification temperature of 333 K, the conversion of oleic acid reached 95.7 % in 4 h. Besides, the beta zeolite membrane reactor exhibited good hydrothermal and acid stabilities with a high oleic acid conversion (maintained above 99 %) after 5 reaction cycles. Through XRD and SEM characterization, it was found that the membrane kept complete crystal structure. Process intensification through a beta zeolite membrane reactor aided by PV was successfully used to enhance the esterification at low temperature in a short time, which was a promising coupling technology.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2021
·Vol. 11
·期 59
·37131-37137
·
IF 3.361
Wen-Yan Pan,Liang-Liang Peng,Wen-Jing Wang,Yuan-Yuan Li,Xue-Ling Wei
Zeolite membranes with unique physical and chemical properties are emerging as attractive candidates for membrane separation. However, defects in the zeolite layer seriously affect their molecular sieving performance. In this study, a novel strategy for preparing compact zeolite membranes on rough supports with the assistance of a reticulated hydrotalcite layer was developed. The reticulated hydrotalcite layer was grown on the inner surface of a 170 mm length ceramic tube by an in situ hydrothermal method, and a NaA zeolite membrane was prepared on this reticulated layer by the microwave-heating method. The hydrotalcite interlayer could not only improve the smoothness and regularity of the surface of the support but also fix the Si/Al active ingredients using its reticulate structure, finally effectively improving the quality and stability of the zeolite layer. The optimal molar ratio of the synthesis solution for the synthesis of the zeolite membrane was 3Na2O : 2SiO2 : Al2O3 : 200H2O. The permeance flux of H2 through the zeolite membrane synthesized under the optimal conditions was high as 0.47 × 10−6 mol m−2 s−1 Pa−1, and its permselectivity for H2 over N2 was 4.7, which was higher than the corresponding Knudsen diffusion coefficient. This study provides a new idea for the preparation of defect-free membranes on rough supports.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2022
·
IF 5.876
Xiuxiu Ren,Huan Yu,Meng Guo,Rong Xu,Jing Zhong
A long alkyl chain-containing organosilica layer obtained from 1, 8-bis(triethoxysilyl)octane (BTESO) was used to modify silicalite-1 membranes via a sol−gel method to obtain bi-layered BTESO/silicalite-1 composite membranes on macroporous α-Al 2 O 3 supports for the recovery of diluted ethanol by pervaporation . Silicalite-1 zeolite membranes were hydrothermally synthesized using two seeding methods: those prepared using wet−rubbing seeding method exhibited larger separation factors than those obtained using the dip−coating method in the pervaporation of ethanol/water due to the thinner seed layer in the former. After modified with BTESO, the surface became smoother and denser with higher hydrophobicity , and the thickness of BTESO layer was approximately 300 nm on both types of membranes. In pervaporation, two types of silicalite-1 membranes unexpectedly showed similar performances after BTESO modification. Ethanol flux increased or was maintained while water flux decreased greatly for silicalite-1 membranes after BTESO coating with increasing sol concentrations, and a higher separation factor was attained without sacrificing ethanol flux. The long alkyl chains in BTESO and silanols reacted with hydroxyl groups in silicalite-1 provided flexibility and hydrophobicity for ethanol transport with minor resistance. The optimized 2.0% BTESO/silicalite-1 membranes synthesized using wet−rubbing method showed a maximum flux of 6.84 kg m −2 h −1 and separation factor of 24.6 with overall pervaporation separation index of 161 in the pervaporation of 5.0 wt% ethanol/water mixture at 60 °C.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Membranes
·
2022
·Vol. 12
·期 12
·1269
·
IF 4.562
Zhengquan Yang,Mingyu Peng,Yu Li,Xiaowei Wu,Tian Gui,Yuqin Li,Fei Zhang,Xiangshu Chen,Hidetoshi Kita
In this work, a dense and acid-resistant beta zeolite membrane was applied to improve the esterification of citric acid and n-butanol, for the first time. Through the continuous removal of the by-product water via pervaporation (PV), the conversion of citric acid was significantly enhanced from 71.7% to 99.2% using p-Toluenesulfonic acid (PTSA) as catalyst. PTSA was a well-known strong acid, and the membrane kept almost no change after PV-esterification, indicating the superior acid resistance of beta zeolite membrane. Compared to the use of acid-resistant MOR zeolite membrane by PV-esterification, a consistently higher conversion of citric acid was obtained using a high-flux beta zeolite membrane. The results showed that high water permeation on the beta zeolite membrane, with good acid resistance, had a strong promoting effect on esterification, leading to an improved conversion. In addition, the citric acid conversion of 97.7% could still be achieved by PV-esterification at a low reaction temperature of 388 K.Keywords:improved esterification;Tributyl citrate;beta zeolite membrane;PV-esterification;high conversion
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2023
·
IF 3.8
Wenwen Zhang,Zhigang Xue,Liyun Cui,Haoliang Gao,Di Zhao,Rongfei Zhou,Weihong Xing
The synthesis of a continuous IMF zeolite membrane was fabricated on tubular substrates by seeded growth for the first time. The straight channels of IMF zeolite with diameters of 0.53–0.59 nm are distinguishable for p -xylene from o -xylene molecules. Pure IMF-phase high-silica IM-5 zeolite seeds with uniform and fine crystal size were fabricated by a new sonication-assisted aging process. The seeds were coated on the support by dipcoating and induced the formation of continuous membrane. Separation performance in p -/ o -xylene mixture was investigated at various temperature and pressure. The typical IM-5 zeolite membrane had p -/ o -xylene separation factor of 3.7. Our results suggest that IM-5 zeolite is a potentially good membrane material for the separation of xylene mixtures.
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
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2020
·
IF 3.99
Ji Guo,Zhongli Ji
The filtration efficiency of coalescent filter elements used in gasoline and diesel oil dehydration in refineries is unsatisfactory and not sufficient to meet downstream water-content requirements. Thus, it was necessary to improve the internal filter medium of traditional oil-water coalescent filter elements. Zeolite membrane is a kind of material with superhydrophilicity and strong adsorption for and permeability to water. In this study, ZSM-5 zeolite membrane with superhydrophilic properties was successfully prepared by an in situ hydrothermal synthesis. Two experiments with zeolite membranes were performed, including membrane filtration and membrane coalescence tests. Membrane filtration tests showed that it possessed strong adsorption for and permeability to water and that the oil-water filtration efficiency for 32 # turbine oil, kerosene, and corn oil were all >95 %. In the second part of this study, composite filtration was carried out using the membrane as well as hydrophilic glass fiber and hydrophobic polypropylene (PP) membranes. Membrane coalescence test demonstrated that, when the oil contained a phenol/water combination, the water rejection rate of the composite filtration with ABACBA (A, PP fiber; B, glass fiber; and C, molecular sieve membrane) was 90.8 %, with the downstream water content controlled within 100 mg/L and the quality factor increased from 0.18 to 0.23, relative to other systems. These experimental results showed potential for improving the current oil-water coalescent filters.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2016
·
IF 3.349
Chen Zhou,Junjie Zhou,Aisheng Huang
In this study, dense and phase-pure zeolite FAU membrane has been prepared on α-Al 2 O 3 tube using a seeding-free synthesis strategy. 3-aminopropyltriethoxysilane (APTES) acts as a molecular linker for anchoring the FAU precursors onto the support surface to promote the nucleation and the formation of a thin, well intergrown zeolite FAU membrane. The obtained membranes are employed for desalination of seawater by pervaporation . With the increase of the synthesis time from 12 h to 24 h at 75 °C, the water fluxes of the zeolite FAU membranes reduce from 4.22 kg m −2 h −1 to 3.42 kg m −2 h −1 at 75 °C due to the increase of the thickness of the zeolite FAU membranes, while the ions rejections increase from 99% to 99.9%. For the zeolite FAU membrane which was prepared at 75 °C for 20 h, with increasing the feed temperature from 30 °C to 90 °C, the water fluxes increase from 0.96 kg m −2 h −1 to 5.64 kg m −2 h −1 , and all the ions rejections of the zeolite FAU membrane are above 99.8%. Note that the zeolite FAU membranes show high separation performances for seawater desalination, even for desalination of 10 wt% seawater, the developed zeolite FAU membranes are very promising in seawater desalination.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Wen-Jing Wang,Wen-Yan Pan,Xue-Ling Wei,Bo Song,Yu-Ling Luo
Zeolite membranes possess great application prospects in purifying chemical substances, however, the current synthetic conditions are insufficient to eliminate defects, restricting the industrial applications of zeolite membranes. In this study, compact X-type zeolite membranes were synthesized in hetero-alkali-metal cation synthesis solutions via in-situ heating method. The obtained X-type zeolite membrane possessed a methanol/methyl tert-butyl ether (MTBE) separation factor greater than 10,000 at a permeation flux of 1.3 kg m −2 h −1 . A possible mechanism for the influence of hetero alkali meatal cations on the formation of zeolite membranes was proposed, which involved structural induction and regulation of the rates of crystal nucleation and growth. The hetero-alkali-metal cations entering the zeolite crystal caused distortion of the crystal structure, which promoted transformation of the zeolite crystal structure and accelerated crystal growth. Meanwhile, the rates of crystal nucleation and growth on the surface of the support were regulated by the cooperative action of the hetero-alkali-metal cations and Na + in the synthesis solution through their solubility for the aluminosilicate gel, leading to the formation of compact zeolite membranes. This method controlled the zeolite crystal structure and compactness of the zeolite membrane by simply adding hetero-alkali-metal cations to the synthesis solution, providing a new idea for designing defect-free membranes with high permselectivity.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）