SEPARATION AND PURIFICATION TECHNOLOGY
·
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
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2017
·
IF 4.601
Dongjing Liu,Weiguo Zhou,Jiang Wu
CuO-based and MnO x -based sorbents modified with Ce and La using sol-gel method, were employed for elemental mercury removal at 120–240 °C. The Hg 0 removal activity of Mn 2 O 3 /ZSM-5 can be significantly enhanced by doping 50 at.% Ce or 10 at.% La, the Hg 0 removal efficiency increased by 94% and 71%, respectively. The Hg 0 removal ability of CuO/ZSM-5 subtly improved by addition of 50 at.% Ce or 10 at.% La, the Hg 0 removal efficiency ascended only by 6% and 18%, respectively. The XPS results revealed that Hg 0 transformed to HgO, and CuO (or Mn 2 O 3 ) was reduced to Cu 2 O (or Mn 3 O 4 ), which is in agreement with Mars-Maessen mechanism.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Zhuo Wang,Huiling Zheng,Fanhui Meng,Tingjun Fu,Zhong Li
The use of ZSM-5@Zn/ZSM-5 core@shell nanocrystals as integrated catalyst for efficient aromatic production from methanol aromatization is demonstrated. By combining the attributes associated with core@shell structural and acidic features, ZSM-5@Zn/ZSM-5 exhibited synergistic and improved catalytic performance toward methanol aromatization. The effect of Zn/ZSM-5 shell thickness and the acid density of the ZSM-5 core on synergistic performance was systematically investigated. Results showed that aromatic selectivity could be increased with shell thickness and the acid density of the ZSM-5 core, while catalytic stability was subject to the optimization on both shell thickness and core acid density. The strengthening of dehydroaromatization on the shell catalyst after Zn introduction and the hydrogen transfer for aromatization with increasing core acid density was confirmed. A double boost on catalytic stability from methanol conversion along with 40.7% increase on aromatic selectivity could be achieved for core@shell catalyst with a coating ratio of 0.3 compared with that on single core catalyst. The fabrication of ZSM-5 core with low SiO 2 /Al 2 O 3 ratio for Zn/ZSM-5 not only provided more acid sites to promote the aromatization, but also promoted the dealkylation of the formed aromatics, which could enhance the selectivity of light aromatics and catalytic lifetime. The findings in the work not only enrich the family of core@shell composite zeolite catalysts, but also provide the fundamental understanding on the aromatization process over core@shell structural features.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
CATALYSIS TODAY
·
2018
·
IF 4.667
Yuexin Peng,Ling Zhang,Yiwen Jiang,Shichao Han,Qiuyan Zhu,Xiangju Meng,Feng-Shou Xiao
Catalytic combustion is considered as an efficient and economic technology to remove VOCs, and Al-ZSM-5 zeolite supported palladium catalysts (Pd/Al-ZSM-5) with good performances in this kind of reactions have been reported. In this work, it is found that Fe-ZSM-5 supported palladium catalyst (Pd/Fe-ZSM-5) exhibit higher catalytic activity in toluene combustion than the Pd/Al-ZSM-5, which is strongly related to more Pd 0 active species and higher concentration of absorbed oxygen species of Pd/Fe-ZSM-5 than those of Pd/Al-ZSM-5. More importantly, Pd/Fe-ZSM-5 has a good catalyst life and water-resistant ability, which should be potentially significant for practical applications in environment protection.
研究领域:
环境科学
·
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
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
·
化学工程
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Xiaoxue Li,Xiaopo Niu,Shuaikang Zhu,Shuang Xu,Zheyuan Wang,Xiangwen Zhang,Qingfa Wang
Fabricating zeolite-supported catalysts with excellent catalytic performance for hydroconversion of bio-oils into high-quality fuels is still a great challenge. Herein, hierarchical ZSM-5 zeolites were successfully synthesized with 3-[(trimethoxysilyl) propyl] octadecyldimethylammonium chloride as a mesoporous template. The hierarchical ZSM-5 supported Pt catalysts (Pt/HZ-x) were used to enhance the hydrodeoxygenation of dibenzofuran into bicyclohexane, and the influence of acidity distribution on the reaction pathways was investigated by tailoring the Si/Al molar ratios (50, 75, and 100). For all catalysts, cycloalkanes were produced via the partial hydrogenation of the aromatic rings to generate tetrahydrodibenzofuran, followed by the cleavage of C—O bond. The optimal bicyclohexane selectivity (86.8%) was obtained on Pt/HZ-75 catalyst due to the good synergistic effect between metal dispersion and acid distribution. This catalyst also showed excellent stability because of its strong metal–support interactions. Even after reused five times, the catalytic activity was almost unchanged compared with the fresh one. Furthermore, the possible reaction pathways for conversion of dibenzofuran into bicyclohexane over Pt/HZ-x catalysts were developed.
研究领域:
催化
·
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Jiaojiao Liu,Huifang Zhang,Ningyue Lu,Xiaoliang Yan,Binbin Fan,Ruifeng Li
A series of mesoporous ZSM-5-x (x = Si/Al molar ratio) supports, possessing various Si/Al ratios, were prepared without using the secondary templates, and the influences of acidity of ZSM-5-x on catalytic performance of Pt/HZSM-5-x samples prepared by the conventional wetness impregnation in naphthalene hydrogenation were investigated. The results show that decreasing Si/Al ratios of mesoporous ZSM-5 supports promotes the dispersion of the supported Pt species, and the catalytic efficiencies of Pt/HZSM-5-x samples for naphthalene hydrogenation depend on the integrated effects of the Pt dispersion, the acidity, and the mesoporous structure of ZSM-5 supports. This work provides the detailed influences of acidity of mesoporous ZSM-5 on catalytic performance of supported Pt catalysts in naphthalene hydrogenation.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 103
·101365-101371
·
IF 3.289
Guang Xiong,Jinpeng Yin,Jiaxu Liu,Xiyan Liu,Zhendong Guo,Liping Liu
Nano-sized ZSM-5 aggregates with interparticle mesopores was synthesized by an aerosol-assisted method. The amorphous aluminosilicate powder was used as a precursor, which was obtained by an aerosol process from an aqueous solution of the silicon and aluminium sources. The amorphous powder was crystallized in an autoclave with the structure-directing agent tetrapropylammonium hydroxide. No extra water was added in this step. The synthesis was performed in an extremely dense system, hence the amount of both template and waste water can be significantly reduced. The formation of the nanocrystalline MFI zeolite is mainly based on the liquid phase transformation in a supersaturation system. The nano-sized ZSM-5 aggregates were composed of nanocrystals with a size of 50–100 nm. Compared with the ZSM-5 zeolite synthesized by a conventional hydrothermal method, the nano-sized ZSM-5 aggregates exhibits a higher BET surface area, external surface area, and total pore volume and better Al species distribution. This nanocrystalline ZSM-5 zeolite shows a higher catalytic activity and stability in catalytic cracking of 1,3,5-triisopropylbenzene.
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
ENERGY & FUELS
·
2022
·
IF 4.654
Jing Li,Suxia Ma,Rongji Cui,Nuo Xu,Ting Pei
Solid waste fly ash can encroach on land, contaminate the environment, and jeopardize human health. An alkali fusion method combined with a hydrothermal method was adopted to prepare fly ash-derived ZSM-5 molecular sieves, and a series of Fe/ZSM-5 catalysts were also prepared to test their catalytic performance in NO oxidation with H2O2. Moreover, the characteristics of catalysts synthesized by fly ash, as well as the relationship between the structure and the catalytic activity, were analyzed in detail through multiple characterization approaches. The results gave important insights into the active sites of catalytic oxidation. They concluded that 10% Fe/ZSM-5 had the best catalytic activity in which Fe sites and Brønsted acid sites collectively provided the catalytic functionality, and 92% NO removal efficiency was obtained achieved under optimal experimental conditions. This work provided a new way for recycling fly ash and developing low-cost catalysts for NO removal.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
ADSORPTION-JOURNAL OF THE INTERNATIONAL ADSORPTION SOCIETY
·
2016
·Vol. 22
·期 3
·327-334
·
IF 1.87
Liu Dongjing,Zhou Weiguo,Wu Jiang
Perovskite LaMnO 3 /ZSM-5 was used for reactive adsorption of hydrogen sulfide at 500–700 °C. The sorbents showed good desulphurization performance, the highest sulfur capacity of 1020 µmol S/g over 5La5Mn/ZSM-5 was obtained at 600 °C. The reducing gases (H 2 and CO) can obviously shorten the breakthrough time and reduce the sulfur capacity. Incorporating Mn ions into La 2 O 3 lattice improved the sulfidation activity due to the formation of perovskite LaMnO 3 with good reducibility and structure stability.
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
ADVANCED POWDER TECHNOLOGY
·
2024
·
IF 4.2
Cheng Wang,Fuling Du,Lipeng Wang,Qianru Yu,Xinchao Liang,Siqi Liu,Zhe Lei
TiO 2 /ZSM-5 composites with enhanced adsorption and photocatalytic properties were synthesized via regulation of synthesis pH value and post (acid/alkali) treatment of ZSM-5. The influences of synthesis pH values and post-treatment of ZSM-5 on microstructure, adsorption and photocatalytic properties of the composites were investigated. The methyl orange was used to assess the adsorption and photocatalytic properties of the samples. The results showed that the synthesis pH values and acid/alkali treatment had significant influences on the microstructure, adsorption and photocatalytic properties of TiO 2 /ZSM-5 composites. The composites synthesized at pH 7 had a relatively higher TiO 2 content, smaller anatase crystallite size, greater specific surface area, the most effective separation of photogenerated electron-hole pairs, the fastest interfacial charge transfer, and therefore exhibited excellent adsorption and photocatalytic properties. Acid treatment could significantly increase the specific surface area, Si/Al ratio of ZSM-5, the separation efficiency of photogenerated electron-hole pairs, and amount of produced active free radicals •O 2 – and •OH. The TiO 2 /acid-treated ZSM-5 exhibited excellent photodegradation with 99.3 % methyl orange in 150 min, which is higher than that of the TiO 2 /ZSM-5 and TiO 2 /alkali-treated ZSM-5.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCES IN POLYMER TECHNOLOGY
·
2020
·
IF 1.539
Yunlong Liu,Jie Guo,Zhuobing Xiao,Dazhao Peng,Ke Song
Separation and purification of active components from biomass by inorganic materials during the pretreatment process of hydrothermal conversion are studied in this work. The batch experiment results show that an initial solution pH of 6 favors chelerythrine adsorption, and the optimum adsorbent dosage is 2.0 g. The adsorption mechanism of ZSM-5 for chelerythrine is investigated by adsorption kinetics, isotherm adsorption models, and thermodynamics analysis. The results show that the kinetics data fit the pseudo-second-order model well (R2 = 0.9991), and the intraparticle diffusion model has 3 diffusion stages, preliminarily indicating that chemisorption plays a major role in the adsorption process, and the sorption mechanism includes intraparticle, external, and boundary diffusion. The adsorption isotherms agree well with the Langmuir model, indicating the occurrence of monolayer molecular adsorption during the adsorption process. Meanwhile, the maximum adsorption capacity is 2.327, 2.072, and 1.877 mg/g at different temperatures (288 K, 298 K, and 308 K), respectively. The thermodynamic data demonstrate that the adsorption process is exothermic and spontaneous in nature. These observed results clearly confirm that ZSM-5 has potential superior properties for the enrichment and purification of alkaloids during the pretreatment of biomass.
研究领域:
生物化学
·
环境科学
·
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）