JOURNAL OF MEMBRANE SCIENCE
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2016
·
IF 5.557
Kai Xu,Chenfang Yuan,Jürgen Caro,Aisheng Huang
In the present work, we report a new road to enhance the gas separation performances of the zeolite Na-LTA membrane by tuning the pore size of zeolite LTA through silver cation exchange. Through the functionalization of the alumina support by using 3-aminopropyltriethoxysilane (APTES), a thin, phase-pure and well intergrown zeolite Na-LTA membrane with a thickness of about 5.0 µm can be facilely prepared on the APTES-modified macroporous α-Al 2 O 3 tube. After a following silver exchange treatment of the as-synthesized zeolite Na-LTA membranes, the sodium ions in zeolite Na-LTA framework are replaced by silver ions , thus forming zeolite Ag-LTA membranes with a narrower pore diameter. The zeolite Ag-LTA membranes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). It is found that both the morphology and structure of the zeolite Na-LTA membrane keep unchanged after silver-exchange, and no cracks, pinholes or other defects are observed in the membrane layer. The zeolite Ag-LTA membrane shows high hydrogen selectivity due to the reduction of pore size of the zeolite Ag-LTA. For the separation of the binary mixture at 50 °C and 2.0 bar, the separation factor of H 2 /C 3 H 8 is α≈120.8, which by far exceeds α≈19.4 of the starting Na-LTA membrane, and are also much higher than the separation factors previously reported for the H 2 /C 3 H 8 mixture on zeolite membranes.
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
APPLIED ORGANOMETALLIC CHEMISTRY
·
2024
·
IF 3.7
Qiuyun Zhang,Ting Li,Zhenying Li,Yanhui Lei,Xingyue Hong,Mei Deng,Jingsong Cheng,Zhengjun Liu,Yutao Zhang
Metal–organic frameworks (MOFs) are ideal supports for the synthesis of porous composite catalysts. In the present study, Sn-Bi bimetallic metal–organic frameworks (Sn-Bi-MOFs) supported silver-doped phosphotungstic acid (AgPW) catalysts (AgPW@Sn-Bi-BDC and AgPW@Sn-Bi-BDC (NH 2 )) were successfully synthesized via a simple in situ impregnation method, which was subsequently applied to catalyze esterification for the production of biodiesel from oleic acid (OA). The physico-chemical properties of the prepared composite catalysts underwent comprehensive analysis through XRD, FTIR, N 2 physisorption, SEM, EDX, NH 3 -TPD, Py-FTIR, TG, and XPS techniques, confirming the successful impregnation of AgPW on the Sn-Bi-MOFs framework. Among the catalysts tested, AgPW@Sn-Bi-BDC (NH 2 ) exhibited the better catalytic activity than that of Sn-Bi-BDC, Sn-Bi-BDC (NH 2 ), and AgPW@Sn-Bi-BDC, reaching 91.6% of OA conversion with the methanol:OA molar ratio of 20:1 and the catalyst quantity of 0.2 g at 130°C for 4 h. The high activity of AgPW@Sn-Bi-BDC (NH 2 ) is attributed to the available multiscale pore structure, high acidity, and the synergistic action of the Brønsted and Lewis acidic sites. Additionally, the esterification with AgPW@Sn-Bi-BDC (NH 2 ) followed the first-order reaction kinetic model, with an E a of 34.5 kJ/mol. Moreover, the recyclability of the composites was also assessed, demonstrating sustained catalytic activity after four reuses. This approach showed a potential for sustainable and efficient energy production through bimetallic MOFs-based composite catalysts.
研究领域:
化学工程
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催化材料
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产品关联
DOI
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
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2014
·
IF 2.063
Yongshen Ren,Bing Liu,Zehui Zhang,Jintao Lin
Three kinds of silver-exchanged phosphotungstic acid catalysts were prepared and used for the synthesis of potential biofuel 5-ethoxymethylfurfural (EMF). It was found that the partially silver exchanged phosphotungstic acid (Ag 1 H 2 PW) showed the best catalytic activity among silver exchanged phosphotungstic acids prepared. The highest EMF yield of 88.7% was obtained from 5-hydroxymethylfurfural (HMF) at 100 °C after 10 h. Furthermore, Ag 1 H 2 PW also showed high catalytic activity for the one-pot conversion of fructose into EMF with a yield of 69.5%. In addition, Ag 1 H 2 PW could be reused several times without a significant loss of its catalytic activity.
研究领域:
化学工程
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可再生资源化学
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2018
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IF 0
Yuying Zhang,Chuang Li,Zhongtian Du,Xiao Chen,Changhai Liang
Transformation of renewable biomass into chemicals has attracted much attention recently. Efficient catalytic dehydration of biomass-derived sorbitol into isosorbide over solid acid catalysts under moderate reaction conditions is still a technical challenge. A series of silver-exchanged phosphotungstic acid catalysts were prepared by an ion-exchanged process, and dehydration of sorbitol into isosorbide was performed under solvent-free conditions. More than 99% conversion of sorbitol was obtained with 83% selectivity of isosorbide over Ag 1 H 2 PW catalyst at 140 °C within 1 h, which are comparable with that using a homogeneous phosphotungstic acid (HPW) catalyst. The silver-exchanged phosphotungstic acid catalysts were characterized by various techniques such as XRD, FT-IR, Raman, NH 3 -TPD and Py-IR to build a relationship between the catalytic activity and their natures. Ag 1 H 2 PW exhibited much higher activity for catalytic dehydration of sorbitol to isosorbide compared with Ag 2 H 1 PW and Ag 3 PW under the same reaction conditions, which was attributed to the stronger acidity and higher amount of Brönsted acid sites. Moreover, Ag 1 H 2 PW could be easily regenerated by 65% HNO 3 solutions and used repeatedly at least 3 times without obvious loss of catalytic activity.
研究领域:
化学工程
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催化
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可再生能源
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产品关联
DOI
Scientific Reports
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2020
·Vol. 10
·期 1
·1-9
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IF 3.998
Chen Xutao,Yu Lisha,Zou Shihui,Xiao Liping,Fan Jie
It is challenging to develop a low-cost household water treatment (HWT) that simultaneously deliver an effective and robust way for safe and reliable water supply. Here, we report a simple flow-through filter made by zeolite-cotton packing in a tube (ZCT) as low-cost HWT device to remove heavy metal ions from contaminated water. The zeolite-cotton is fabricated by an on-site template-free growth route that tightly binds mesoporous single-crystal chabazite zeolite onto the surface of cotton fibers. As a result, the ZCT set-up with optimized diameter achieves both high adsorption efficiency, proper flow rate, reliable supply and strong stability at the same time. After flowed through the set up packed with 10 g of zeolite-cotton, 65 mL 1000 ppm Cu 2+ solution was purified down to its safety limit (<1 ppm). Notably, their efficiency remains unaltered when filtering several ions simultaneously. In a simulated purification process, 8 L of water contaminated by Cu 2+ , Cd 2+ and Pb 2+ could be transformed into drinking water and it enables the removal of heavy metals to concentrations of below 5 ppb (μg L −1 ). We also show that the ZCT can be used for disinfection by introducing Ag-exchanged zeolite-cotton without contaminating the water with Ag ions (<0.05 ppm).
研究领域:
环境科学
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水处理
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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
危险品化学品经营许可证（带存储）