CHEMICAL ENGINEERING SCIENCE
·
2025
·
IF 4.3
Yu Zhou,Ning Li,Caiping Ma,Xiaohua Shen,Xiaofeng Li,Baojun Wang,Lixia Ling
Ga-ZSM-5 zeolite has excellent performance for methanol to aromatics (MTA) reactions, but introducing Ga metal into ZSM-5 zeolite leads to a complex acid species. The present study investigated the effect of Ga metal content on the acid amount and MTA reaction products in the hydrothermal synthesis of Ga-ZSM-5 zeolite. Lewis acid mainly formed at a Ga/Al ratio below 2.0, and at a Ga/Al ratio higher than 2.0, framework Ga species formed, increasing Brønsted acid content. Ga 2.0 -ZSM-5 zeolite exhibited the lowest B/L acid ratio (0.48), excellent BTX selectivity (40.26%), and the highest H 2 selectivity (8.93%). This finding indicates the most pronounced synergistic hydrogenation of Brønsted and Lewis acids. Ga 3.0 -ZSM-5 produced more xylene with more Brønsted acid compared to Ga 1.0 -ZSM-5, although they both had the same B/L acid ratio. The alterations in acidic species at different content of Ga metal appear to be conducive to the regulation of acidity in Ga-ZSM-5 zeolites.
研究领域:
化学工程
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催化材料
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2022
·Vol. 38
·期 4
·1083-1088
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IF 2.726
Xiao Peiwen,Li Hui,Wang Pingmei,Liu Bolun,Jing Wendan,He Lipeng,Wang Runwei,Han Xue,Zhang Zongtao,Qiu Shilun,Luo Jianhui
Herein, we propose a novel approach to reduce the viscosity of heavy oil by functional hierarchical CTMS-ZSM-5-PTMS zeolites. CTMS-ZSM-5-PTMS zeolites synthesized by asymmetric modification and selective alkali etching can reduce the viscosity of heavy oil through adsorbing asphaltenes. This method can reduce the viscosity of heavy oil from hundreds of thousands mPa·s to about ten thousand mPa·s. The work provides an economical and environmentally friendly candidate for heavy oil viscosity reduction under low-temperature conditions.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2024
·
IF 4.8
Tianyu Bai,Jinquan Tao,Yijing Jia,Wenbin Huang,Rongpeng Yao,Xinan Xue,Yasong Zhou,Qiang Wei
In the research of directly synthesizing H-form ZSM-5, ammonium hydroxide is commonly used as an alkali source instead of NaOH to avoid multiple ion exchange steps. However, the volatile nature and the lack of structure-directing effect of ammonium hydroxide limit its application in practical. In this study, n -butylamine (NBA) was used as the main alkali source to directly prepare HZSM-5 zeolites with SiO 2 /Al 2 O 3 ratios ranging from 40 to 300 under traditional hydrothermal conditions. The influence of the amount of NBA, ethanol, seed, and pre-crystallization on the synthesis products was investigated under the condition of SiO 2 /Al 2 O 3 = 80. Theoretical simulation suggested that n -butylamine cations (NBA + ) play the most potent directing role in the formation of the MFI structure but could lead to difficulties in removal during calcination. The addition of ethanol as the zeolite growth modifier (ZGM) could decrease the usage of NBA and reduce the difficulties in calcination, and the addition of seed provided the conditions for initiating crystallization in the system that could not spontaneously nucleate. HZSM-5 with different SiO 2 /Al 2 O 3 ratios were prepared under the optimal crystallization conditions, and the as-synthesized samples exhibited superior textural and acid properties compared to commercial zeolite. Finally, the 1 L scale-up synthesis and MTP reaction were conducted to demonstrate the practicality of this economically and environmentally-friendly synthesis strategy.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2022
·
IF 4.889
He Han,Anfeng Zhang,Limin Ren,Xiaowa Nie,Min Liu,Yi Liu,Chuan Shi,Hong Yang,Chunshan Song,Xinwen Guo
Shape-selective alkylation of toluene with methanol is one of the most attractive promising synthetic routes to para -xylene. To date, modified ZSM-5 zeolites are considered to be one of the best candidate catalysts for this reaction. Although the para -selectivity could be tuned to approaching 100% by modification of the zeolite and optimization of reaction conditions, at present, there is still a lack of effective means to inhibit the rapid deactivation of the catalysts due to coke formation. In this work, a coke-resistant (Pt + Ni)/ZSM-5 zeolite with excellent stability for shape-selective alkylation of toluene with methanol to para -xylene is developed. The pore structure and acid properties of the zeolite are effectively tuned to ensure high para -selectivity. Meanwhile, the co-existence of Pt and Ni species in this catalyst plays the critical role in inhibiting coke formation, as the two species concurrently impede the formation of olefins, the main coking precursors, via two distinctive mechanisms.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2022
·
IF 9.136
Yonghou Xiao,Jiahui Fu,Heyang Zhu,Qidong Zhao,Liang Zhou
The diffusion limitation owing to the long and narrow pore structure in traditional ZSM-5 zeolite could restrain the adsorptive desulfurization performance towards thiophene sulfur compounds from fuels. Herein, ZSM-5 zeolite nanocrystals were successfully fabricated using steam-assisted gel crystallization strategy to control the size of zeolite particles within 70 ∼ 160 nm. Compared to traditional micron ZSM-5, ZSM-5 zeolite nanocrystals could effectively reduce the diffusion pathway, enlarge the specific surface area, and increase exposure of adsorption sites, which could enhance the desulfurization performance. ZSM-5 nanocrystals with a mole ratio SiO 2 /Al 2 O 3 of 200 exhibited a satisfactory desulfurization efficiency, and the breakthrough capacity attained 0.0509 mmol S/g adsorbent. After ZSM-5 nanocrystals were ion-exchanged with NH 4 + and Ag + , both mesoporous characteristics and the Lewis acid (L-acid) sites were enhanced, which promoted the adsorption desulfurization performance. Furthermore, nanocrystalline ZSM-5 and Ag/ZSM-5 also exhibited acceptable regeneration performance. This study is expected to provide an effective strategy and a facile method to prepare nanocrystalline ZSM-5 based adsorbents for the development of efficient desulfurization materials.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Crystals
·
2021
·Vol. 11
·期 10
·1247
·
IF 2.589
Changsheng Zhang,Kai Fan,Ge Ma,Chi Lei,Wei Xu,Jie Jiang,Bing Sun,Hongxing Zhang,Yunfeng Zhu,Song Wen
Hierarchical zeolites attract people’s attention due to their enhanced mass transfer properties in catalytic reactions. The research over obtaining these zeolites in green and efficient methods is of great significance for the current post-treatments and templating strategies tend to be costly for hierarchical zeolite synthesis. In this research, nanosized mesoporous ZSM-5 (SN-ZSM-5) zeolites have been synthesized without the addition of mesoscale templates under highly concentrated conditions. The physicochemical characteristics were systematically investigated by XRD, SEM, N2 sorption, TEM, and NMR. The SEM images showed ZSM-5 crystals with sizes between 50–110 nm were obtained. N2sorption and high-resolution TEM images gave direct evidence for the hierarchical structure of SN-ZSM-5. The forming mechanism for the hierarchical structure was proposed that the etching effect of the highly alkaline environment for the starting gels played a critical role in the formation of hierarchical structure. Catalytic tests in methanol-to-olefins (MTO) showed the SN-ZSM-5 performed a longer catalyst lifetime and higher propylene selectivity than the conventional ZSM-5 zeolites (C-ZSM-5) obtained from a traditional hydrothermal method. The features of hierarchical structure in the SN-ZSM-5 crystals and the sustainability for synthesis method could show a promising choice for wide applications of these SN-ZSM-5 zeolites in the future.Keywords:ZSM-5 zeolite;efficient synthesis;hierarchical;nano crystals
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
BIOMASS & BIOENERGY
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2023
·
IF 6
Lihe Zhu,Xueting Shao,Xuejun Pan,Zhong Sun,Xiangyu Li,Xixin Duan,Junyou Shi
Catalytic conversion of waste biomass to furfural (FF) is an important valorization of lignocellulose . Heteropolyacid catalysts were designed for efficient aqueous-phase dehydration of saccharides by supporting phosphotungstic acid (H 3 PW 12 O 40 , abbreviated as PW 12 ) on H-ZSM-5 zeolite at different loadings (xPW 12 /ZSM-5, x = 10%, 20%, 30%, 40%, 50%). The PW 12 /ZSM-5 was used in the one-pot conversion of biomass (xylose, xylan , and corn stover) to FF in LiBr aqueous solution. The low PW 12 loading catalyst (10%PW 12 /ZSM-5) could efficiently convert biomass to FF with the yields of 73.3% (xylose) and 75.1% (xylan) at moderate temperature (130 °C), respectively. The PW 12 loading and acid sites distribution were crucial to the catalytic performance. Moreover, LiBr enhanced the yield of FF because of its Lewis acidity. The PW 12 /ZSM-5 based solid polyacid was a promising catalyst for the efficient FF production from biomass with high yield and easy separation.
研究领域:
生物化学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2022
·
IF 5.876
Xiuli Shao,Siqi Wang,Youhui Zhou,Xuan Zhang,Haizhou Tian,Zheng Wang,Zhong-Yong Yuan,Huanting Wang
The ZSM-5 zeolite nanosheets are highly desired materials for catalytic reactions and membrane separation . Their synthesis depends on specially designed complex surfactants ; however, the high-cost limits their large-scale industrial production. Herein, the tailored synthesis of coffin-shaped multilamellar ZSM-5 composed of orderly stacked 2D nanosheets is carried out using cetyltrimethylammonium bromide (CTAB) as a structure-directing agent (SDA) in the presence of silicalite-1 seed sol. The morphology and b -axis thickness of nanosheets is controlled by adjusting the amount of silicalite-1 seed sol, CTAB/TEOS ratio, SiO 2 /Al 2 O 3 ratio, and synthesis time. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis indicate that the hydrophobic tail of CTAB acts as an inhibitor, effectively preventing the continuous growth along b -direction with an average thickness of 20–100 nm. This work highlights the role of silicalite-1 seed sol and CTAB in the orderly stacked sheets growth process. This crystallization strategy opens a facile and inexpensive approach for multilamellar ZSM-5 zeolite fabrication with 2D-nanosheets structures, and their practical applications in catalytic conversions of bulky molecules.
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
NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 29
·13993-14001
·
IF 3.3
Wenhui Wu,Conger Deng,Qian Lei,Honglin Chen
ZSM-5 could be a good candidate for the catalysis of formaldehyde to trioxane (TOX) because of its appropriate and adjustable acid properties. However, the space-time yield (STYTOX) and selectivity of the TOX catalyzed by ZSM-5 zeolites are relatively low at present. [Ga, Al]-MFI zeolites containing different Ga/Al atomic ratios were used as catalysts for reaction of synthetic TOX. The structural information of the materials was illustrated by characterization through XRD, ICP-OES, XPS, SEM, BET analysis, and MAS NMR spectroscopy. And the acid properties of the materials were tested by NH3-TPD and Py-IR. The catalytic performance test showed that the STYTOX of [Ga, Al]-MFI-50 is about twice that of ZSM-50 or [Ga]-MFI-50. And the selectivity of TOX is also significantly improved compared to that with [Al]-MFI-50 and Ga-MFI-50. This is because the introduction of Ga atoms into ZSM-5 causes the Brønsted acid content to rise, resulting in STYTOX. It is worth noting that adjusting the Ga/Al atom ratio in the framework affects the B/L value of the zeolite, which leads to the optimization of the selectivity.
研究领域:
化学工程
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Water Process Engineering
·
2024
·
IF 6.3
Jing Li,Suxia Ma,Nuo Xu
The pursuit of carbon peaking and carbon neutrality goals necessitates flexible operation and deep peaking of coal-fired units, thus placing heightened demands on nitrogen oxide (NO X ) emission control. Fly ash, a solid waste rich in silicon (Si) and aluminum (Al), should be fully leveraged, and the high-value synthesis of zeolite represents a viable utilization method. In this context, fly ash-based zeolite was prepared as a catalyst to facilitate the generation of active oxides from H 2 O 2 , combined with alkali solution absorption, to achieve efficient denitrification. This approach effectively transforms ‘waste to pollution’ mitigation. The optimal synthesis conditions for FA-ZSM-5 zeolite were established using the alkali fusion hydrothermal synthesis method, with fly ash as the raw material. The specified conditions were NaOH/FA = 1.2, SiO 2 /Al 2 O 3 = 40, H 2 O/Al 2 O 3 = 1325, TPAOH/Al 2 O 3 = 10, ZSM-5-seed addition of 5 %, and a hydrothermal temperature and time of 140 °C for 24 h. Experimental parameters were meticulously investigated to ascertain their impact on nitric oxide (NO) removal efficiency. The highest removal efficiency was achieved under specific conditions: a reaction temperature of 140 °C, an H 2 O 2 concentration of 6 %, a catalyst dose of 0.3 g, an NO concentration of 600 mg/m 3 , and an SO 2 concentration of 1000 mg/m 3 . Finally, analysis of the catalytic oxidation mechanism revealed that H 2 O 2 , when catalyzed by FA-ZSM-5 zeolite, generates ·OH radicals with strong oxidizing properties, thereby facilitating the oxidative removal of NO.
研究领域:
环境科学
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材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2024
·
IF 4.8
Mengkun Luan,Xiangjie Lei,Yu Fan
To increase the yield of light olefins during the catalytic pyrolysis of alkanes, a novel hierarchical Fe-incorporated ZSM-5 molecular sieve (FeM-Z5) was synthesized using an Fe-based metal-organic framework (Fe-MOF) as a mesoporogen and iron source through the dry gel conversion (DGC) method. In contrast to the conventional method of incorporating Fe species into ZSM-5 via impregnation, the DGC method incorporates Fe species into the framework of ZSM-5, decreasing the amount of Brønsted (B) acid sites and thereby inhibiting the side reactions of hydrogen transfer during the catalytic pyrolysis of alkanes. Compared with the FeN-Z5 catalyst prepared by the DGC method with Fe(NO 3 ) 3 as an iron source, FeM-Z5 had a larger amount of strong B acid sites and more mesopores with a size range of 10–40 nm originating from the decomposition of Fe-MOF; these aspects improved n-pentane pyrolysis and ethylene and propylene diffusion. As a result, the optimal FeM-Z5 catalyst exhibited the highest yield of ethylene and propylene (33.4 wt%) and the lowest deactivation rate (0.07 %/h) among the prepared catalysts during the catalytic pyrolysis of n-pentane.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
Crystals
·
2020
·Vol. 10
·期 9
·781
·
IF 2.404
Qintong Huang,Rui Li,Guangying Fu,Jiuxing Jiang
ZSM-5 zeolites are commonly used as a heterogeneous catalyst for reactions. Four ZSM-5 catalysts (with various crystallite sizes and a similar ratio of Si/Al) and their ball-milling/surface-poisoning derivates were used to convert L-lactic acid to L, L-lactide. The reaction products were analyzed by three independent analytical methods (i.e., Proton nuclear magnetic resonance (1H NMR), high-pressure liquid chromatography (HPLC), and chiral gas chromatography (GC)) for determining the L, L-lactide yield and L-lactic acid conversion. A clear size effect, i.e., smaller catalysts providing better performance, was observed. Further ball-milling/surface-poisoning experiments suggested that the size effect of the ZSM-5 catalysts originated from the diffusion-controlled nature of the reaction under the investigated conditions.Keywords:ZSM-5 zeolites;L,L-lactide;size effect;diffusion control
研究领域:
催化化学
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材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）