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
FUEL
·
2023
·
IF 7.4
Yinan Wang,Xuteng Zhao,Ting Chen,Zuwei Zheng,Rijing Zhan,He Lin
Pd/SSZ-13 with different Al distributions were hydrothermally synthesized and utilized as passive NOx adsorbers (PNA). The characterization results indicated that more concentrated Al distribution can not only improve the ion-exchanged level of Pd but also generated more Z 2 Pd 2+ sites at six-member rings. Thus, as revealed by NOx adsorption experiments, samples with more Z 2 Pd 2+ sites showed high NOx storage capacity as well as stronger water resistance. Besides, 84.8 % adsorption capacity of this sample was retained after hydrothermal aging treatment. On the other side, Pd existed as [Pd(OH)] + sites on SSZ-13 with isolated Al as the majority. These sites were vulnerable to H 2 O and less stable. Seriously Pd agglomerated was observed on the aged Pd/SSZ-13 with less paired Al. This study revealed that proper Al distribution on SSZ-13 could significantly improve the performance and stability of the catalyst and provided a new direction for the design of PNA catalysts.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2025
·
IF 3.9
Kai Fan,Shuo Liu,Ye Ma,Qinming Wu,Sen Wang,Andree Pauschinger,Andrei-Nicolae Parvulescu,Nils Bottke,Toshiyuki Yokoi,Dirk E. De Vos,Xiangju Meng,Weiping Zhang,Feng-Shou Xiao
ITR zeolites exhibited excellent performance in methanol to propylene (MTP), where an important factor was the Al distribution of the ITR zeolites. However, optimization of the Al location in ITR zeolites in the conventional synthesis is challenging. In this work, the Al distribution in the ITR zeolites was efficiently adjusted by adding boron species in the synthesis gels due to the competitive occupancy of T sites in zeolites between boron and aluminum species. The obtained ITR with different boron content zeolites displayed similar nanosheet morphology, textural parameters, and strong acidic concentration but characterizations of Al distribution showed that the addition of boron species led to more Al species distributed in a relatively small sinusoidal channel and less Al species located in an intersection cavity. As a result, the aromatic cycle would be effectively suppressed due to the steric configuration of large aromatic cycle intermediates, whereas the alkene cycle will be enhanced correspondingly. As expected, catalytic tests in the conversion of MTP showed that the new ITR zeolites exhibited enhanced propylene selectivity and catalyst lifetime with the incorporation of boron species, which was attributed to different Al distribution in these ITR zeolites.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2022
·
IF 5.723
Shipei He,Sheng Fan,Kai Yuan,Shujia Guo,Sen Wang,Zhangfeng Qin,Mei Dong,Weibin Fan,Jianguo Wang
Herein, K + was added in the synthesis gel to regulate the distribution of acid sites in the ITQ-13 zeolite and enhance its catalytic performance in the conversion of methanol to olefins (MTO). The results indicate that a proper content of K + ions in the synthesis gel can not only expedite the crystallization of ITQ-13 zeolite, but also significantly decrease the proportion of paired Al and distribute more Al atoms in the 10-ring sinusoidal channel out from the intersection cavity. Accordingly, over the H-ITQ-13(0.3 K) zeolite prepared using the synthesis gel with a KCl/Al 2 O 3 molar ratio of 0.3, the alkene cycle of MTO keeping to the dual cycle hydrocarbon pool (HCP) mechanism is preferably enhanced, whereas the hydride transfer and aromatization reactions are substantially suppressed. As a result, H-ITQ-13(0.3 K) exhibits much longer catalytic lifetime and higher selectivity to propene and butene , in comparison with the H-ITQ-13 counterpart obtained without adding K + .
研究领域:
化学工程
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催化材料科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2024
·
IF 15.7
Kai Fan,Qinming Wu,Shuo Liu,Haiyu Kong,Sen Wang,Eduard Kunkes,Trees De Baerdemaeker,Andrei-Nicolae Parvulescu,Nils Bottke,Toshiyuki Yokoi,Dirk E. De Vos,Xiangju Meng,Weiping Zhang,Feng-Shou Xiao
Adjusting location and distribution of Al sites in the zeolite framework is critical for catalysis, and typical strategies include using zeolites as starting Al source. However, this approach is still challenging for aluminosilicate ITH zeolite. Herein, the distribution of Al species in the framework of ITH was efficiently regulated by implementing LTA zeolite as the aluminum source added in the starting gels (LTA-ITH). The obtained LTA-ITH zeolites have similar nanosheet morphology, textual parameters, and acidic properties to those of conventional ITH synthesized from boehmite (C-ITH), while the results of 27 Al MAS NMR spectra and 1-hexene cracking indicate that they have a different Al distribution. The use of LTA zeolite in starting gel is favorable for the formation of more Al species in sinusoidal and straight channels, compared with the C-ITH. Catalytic tests in the conversion of methanol to light olefin showed that LTA-ITH exhibited enhanced catalyst lifetime and propene selectivity compared with the C-ITH, which is reasonably attributed to the different locations of Al species in their respective ITH frameworks.
研究领域:
化学
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2019
·Vol. 9
·期 24
·7034-7044
·
IF 5.726
Liwei Zhang,Huaike Zhang,Zhiqiang Chen,Qiang Ning,Suyao Liu,Jie Ren,Xiaodong Wen,Yong-Wang Li
To correlate the relationship between the Al distribution and the catalytic performance of long-chain olefin aromatization, several ZSM-5 zeolites with different Al locations and proximities were prepared via adjusting the hydrothermal synthesis conditions. Characterization by XRD, SEM and N2-adsorption indicated that all the as-prepared ZSM-5 zeolites exhibited high crystallinities, uniform morphologies and open channels. However, a great difference in the framework Al (AlF) positions was observed by 27Al MAS NMR and UV-vis-DRS of Co(II) ions, thus leading to the distinct acidity of various zeolites as determined by NH3-TPD and Py-IR. In 1-octene aromatization reaction, ZSM-5 catalysts exhibited significantly different catalytic performances and reaction pathways, which were closely related to the types and locations of the AlF atoms. The ZSM-5 zeolite catalyst with the most abundant single Al sites exhibited the lowest aromatics selectivity, while Al pairs in the framework were more favorable to the formation of aromatics. Moreover, the product distribution revealed that the Al pairs in the channel intersections of the ZSM-5 zeolite were responsible for the improved selectivity to heavy aromatics due to the fewer space restrictions; however, the Al pairs in the sinusoidal and straight channels with severe size restrictions suppressed the generation of bigger aromatics on the Al sites. This result provided a new potential method for precisely tailoring the catalytic selectivity in olefin conversion and upgrading the Fischer–Tropsch oil.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Petroleum Science
·
2025
·
IF 6.1
Chuan-Hao Zhang,Qi Dong,Fei Wang,Ning-Yue Lu,Feng Yu,Bin-Bin Fan,Rui-Feng Li
Deep hydrogenation of polycyclic aromatic hydrocarbons (PAHs) into jet fuel is an important strategy for the upgrading of light cycle oil (LCO). Zeolite-supported metal catalysts have exhibited good catalytic performance for hydrogenation of PAHs under relatively mild conditions. However, the impacts of acidity variations in zeolite supports, arising from the differences in framework Al (Al F ) distribution on the catalytic behavior of zeolite-supported metal catalysts in the deep hydrogenation of PAHs remains unclear. Herein, two series of mesoporous ZSM-5 samples, that is ZSM-5-E- x and ZSM-5-F- x , with the differences in Al F distribution but similar Si/Al ratios, were prepared in the crystallization system with or without NaOH. The results of NH 3 -TPD, Pyridine-IR, N 2 adsorption-desorption and SEM reveal that two series of HZSM-5 samples have similar acid density and acid strength, textural properties, morphology and particle size. However, the results of XPS, 27 Al MAS NMR, 2,6-Ditert-butylpyridine-IR, catalytic cracking of 1,3,5-triisopropylbenzene and the controlled reactions as well as DFT calculation indicate that the higher enrichment degree of Al F on the external surface and the suitable arrangement mode of Al F in ten-membered ring (10-MR) of HZSM-5-F- x compared to HZSM-5-E- x in case of the similar Si/Al ratios, result in Pt/HZSM-5-F- x exhibiting remarkably-improved deep hydrogenation performance of phenanthrene (PHE) compared to Pt/HZSM-5-E- x . Particularly, the selectivity to perhydrophenanthrene (PHP) over Pt/HZSM-5-F-50 can reach above 99.0% at a conversion of PHE (>99.0%). Furthermore, Pt/HZSM-5-F-50 exhibits well reusability. This work helps to clarify the impact of Al F distribution in ZSM-5 on catalytic hydrogenation performance for PAHs, providing valuable guidance for design and development of efficient catalysts for the hydrogenation of PAHs.
研究领域:
催化化学
·
石油炼制
·
材料化学
·
表面科学
·
工业催化
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Puxiang Yan,Haiyong Wang,Yuhe Liao,Pengyao Sun,Chenguang Wang
Catalytic valorization of biomass into chemicals and fuels plays a key role in order to achieve net-zero greenhouse gas emissions. Herein, a series of hierarchical ZSM-5 zeolites were synthesized by the post-treatment method to transform furfural alcohol (FAL) to levulinic acid (LA). ZSM-5 obtained from tandem alkaline treatment (0.2 M NaOH) and acid washing (0.1 M HCl), denoted as ZSM-5-OH 0.2 -H, exhibited the highest activity, affording 76.2% LA yield in 9:1 acetone–water mixed solvents at 393 K for 0.5 h. The enhanced adsorption capacity and acid accessibility of FAL on zeolite mediated by the introduction of mesopores, as well as the reduced secondary reactions of the generated LA due to few Al atoms in straight and sinusoidal channels (as confirmed by UV–vis diffuse reflectance), were responsible for the outstanding catalytic performance of ZSM-5-OH 0.2 -H. The structure–activity relationship revealed that regulating the porous structure and Al distribution of ZSM-5 was an effective strategy to enhance its hydrolytic performance of FAL to LA. Moreover, ZSM-5-OH 0.2 -H could be reused for three reaction cycles without significant loss in catalytic activity.
研究领域:
化学工程
·
催化
·
生物质转化
·
可持续化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）