INDUSTRIAL CROPS AND PRODUCTS
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2023
·
IF 5.9
Haoran Yuan,Chengyu Li,Rui Shan,Jun Zhang,Yong Chen
In the present study, selective transformation of waste cassava residues into aromatics via catalytic pyrolysis over as-prepared La and P modified ZSM-5 was systematically investigated, especially in the aspects of product regulation and kinetic analysis. Comprehensive physicochemical characterizations were undertaken for unveiling the essential structural properties of La and P modified ZSM-5. The introduction of La and P species significantly enriched the Lewis and Brønsted acid sites in ZSM-5, thus facilitating the directional pyrolysis of waste cassava residues into aromatics. Higher apparent activation energy for aromatics formation from waste cassava residues pyrolysis in the presence of La and P modified ZSM-5 might be due to the fact that the catalytic pyrolysis belonged to diffusion-controlled gas-solid reaction. In comparison with that of the parent ZSM-5, LaP 2 /ZSM exhibited better performance towards aromatics formation in waste cassava residues pyrolysis, wherein the relative content of aromatics reached 83.3% at a temperature of 650 °C. Gratifyingly, the relative content of aromatics was increased to 90.5% for the catalytic pyrolysis of acid pretreated cassava residue, in the case of LaP 1 /ZSM catalyst.
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2023
·
IF 5.2
Rui-Li Yu,Qian-Fan Li,Hao-Ran Sun,Zhen-Le Li,Liang-Zhi Xia
In order to efficiently and rapidly capture radioactive iodine that impacts the environment, this study involves impregnating Tetraethylenepentamine (TEPA) into ZSM-5 zeolite with varying Si/Al ratios and evaluating its adsorption performance towards iodine. It is found that the optimal preparation level is 30 %, leading to a significant increase in the saturated adsorption capacity compared to non-impregnated molecular sieves , with a four-fold improvement. The adsorption rate is also enhanced. Various amines are utilized for impregnation, and FT-IR and molecular computation techniques are employed to investigate the adsorption mechanisms between these amines and iodine. The discovery reveals potential interactions between the amine groups and iodine, such as N ⋅ ⋅ ⋅ I halogen bonding and N–H ⋅ ⋅ ⋅ I hydrogen bonding . These findings provide valuable insights for developing iodine adsorbents, offering promising solutions for protecting ecological and living environments.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Guohao Xu,Xuedong Zhu
A core-shell structured Zn/SiO 2 @ZSM-5 catalyst was prepared by a hydrothermal coating method, and its physicochemical properties and catalytic performance in methane co-aromatization with propane were studied using a conventional solid catalyst (Zn/ZSM-5) as the comparison. Results revealed that methane was activated on Zn sites to form a large number of Zn methyl species and then incorporated during the aromatic formation process to promote the formation of aromatics. At a space velocity of 3600 mL g −1 h −1 and the reaction temperature of 550 ℃, the methane, propane conversion and the aromatics selectivity of Zn/SiO 2 @ZSM-5 catalyst were 7.9 %, 95.9 % and 88.1 %, respectively, which were higher than those of Zn/ZSM-5 catalyst by 2.8 %, 6.7 % and 6.8 %, respectively. The unique reaction pathway of core (Zn/SiO 2 , Zn sites)-shell (ZSM-5, acid sites) was mainly responsible for the superior performance in methane co-aromatization with propane. Meanwhile, the core-shell structured Zn/SiO 2 @ZSM-5 catalyst aroused the formation of distinct micro-macroporous system, which facilitated quick diffusion of desired products out of the intraframework channels and inhibited the formation of carbon deposits. These features of Zn/SiO 2 @ZSM-5 catalyst granted it superb diffusion ability and unique core-shell structure, which greatly enhanced the methane, propane conversion and aromatic selectivity together with a preeminent catalytic stability.
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CHEMICAL ENGINEERING RESEARCH & DESIGN
·
2020
·
IF 3.35
Yue Zhou,Huiping Zhang,Ying Yan
CuO/ZSM-5/PSSF was synthesized by a combined wet lay-up papermaking, secondary growth and chemical vapor deposition (CVD) method for the catalytic oxidation of ethyl acetate in the fixed bed reactor. Ethanol and acetaldehyde are found during the oxidation and 3 wt% CuO/ZSM-5/PSSF catalyst exhibited the best performance with 90% conversion of 1500 ppm ethyl acetate at 254 °C with GHSV of 15,000 h −1 , and the CuO/ZSM-5/PSSF exhibits low byproducts selectivity compared to granular CuO/ZSM-5 catalyst. Furthermore, the 3 wt% CuO/ZSM-5/PSSF catalyst exhibits a high stability after being used at 262 °C for 48 h.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Fuxiang Feng,Li Wang,Xiangwen Zhang,Qingfa Wang
HZSM-5 zeolite has been extensively utilized in the petrochemical and fine chemical industry owing to its excellent isomerization/cracking activity and hydrothermal stability. However, it still remains a great challenge for ZSM-5-supported catalysts to upgrade vegetable oils to aviation-fuel-range-alkanes (AFRAs). Herein, an efficient Ni/ZSM-5 catalyst composed of self-pillared (SP) nanosheets along with high external acid fraction and short characteristic diffusion length was synthesized and employed for this reaction. This SP Ni/ZSM-5 nanosheet catalyst shows high deoxygenation, cracking/isomerization activity, and excellent catalytic stability for upgrading oleic acid to AFRAs, which is attributed to the SP nanosheet structure and reasonable acid distribution. Last, a high AFRA yield of 40% with an iso/n-alkanes ratio of 1.8 was achieved.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Jian Zhang,Liang Wang,Zhiyi Wu,Hai Wang,Chengtao Wang,Shichao Han,Feng-Shou Xiao
We report the synthesis of Zn/ZSM-5 particles coated with a silicalite-1 zeolite shell (core–shell Zn/ZSM-5@silicalite-1) via grinding of the raw silica source materials with TPAOH and Zn/ZSM-5, followed by solvent-free crystallization at 180 °C for 72 h. The product was well characterized by the XRD patterns, N2 sorption isotherms, SEM images, and TEM images. Because of the core–shell structure, the Zn/ZSM-5@silicalite-1 sample exhibits high selectivities for benzene, toluene, and xylenes in the conversion of methanol, compared with those over ZSM-5 and Zn/ZSM-5 samples. The solvent-free synthesis offers an alternative method for preparing core–shell Zn/ZSM-5@silicalite-1 catalysts.
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CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Xiaoxia Ou,Fotios Pilitsis,Yilai Jiao,Yong Zhang,Shaojun Xu,Martin Jennings,Yi Yang,S.F. Rebecca Taylor,Arthur Garforth,Huiping Zhang,Christopher Hardacre,Ying Yan,Xiaolei Fan
Structured Fe-ZSM-5 zeolite supported on silicon carbide (SiC) foam catalyst was develop and applied as the packed foam bed catalytic reactor (FBCR) to the liquid phase catalytic wet peroxide oxidation (CWPO) of phenol under flow conditions. Fe catalysts were uniformly incorporated into ZSM-5 coatings using chemical vapour deposition (CVD). Fluid flow analysis of FBCR was performed by varying liquid flow rate, showing the transition of reactor type from the plug flow reactor to the continuous stirred tank reactor at about 1 ml min −1 . Systematic investigation of CWPO within Fe-ZSM-5/SiC FBCRs identified the optimum condition of operating the FBCR (80 mm bed length) as at 60 °C and 1 ml min −1 with the turnover frequency (TOF) of 95 h −1 for phenol degradation (apparent activation energy = 3.4 kJ mol −1 ) and total organic carbon (TOC) conversion of 45.5%. It was believed that the enhanced macromixing promoted by cellular foam supports was accountable for the observed catalytic performance. The longevity of FBCR under flow conditions was also assessed, showing its good stability over 24 h, as well as the potential for practical adoption.
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GREEN CHEMISTRY
·
2014
·Vol. 16
·期 5
·2580-2586
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IF 6.852
Anqing Zheng,Zengli Zhao,Sheng Chang,Zhen Huang,Kun Zhao,Hongxiang Wu,Xiaobo Wang,Fang He,Haibin Li
We firstly propose the coupling conversion of bio-derived furans and methanol over ZSM-5 for enhancing aromatic production. The coupling conversion of bio-derived furans and methanol was conducted in a continuous fixed bed reactor. 2-Methylfuran (MF) was used as a probe molecule to identify the possible reaction pathways. The effects of the methanol to MF molar ratio, reaction temperature and weight hourly space velocity (WHSV) on the product distribution from the coupling conversion of MF and methanol were investigated. The experimental results showed that the aromatic yield from the coupling conversion of MF and methanol is about 5.2 times higher than that of the catalytic fast pyrolysis of only MF. In addition, it can also enhance the yield of olefins, the selectivity of xylenes and reduce coke formation. These results indicate that there is a significant synergistic effect between MF and methanol. The synergistic effect could be attributed to the methanol-to-olefins reactions, the Diels–Alder reactions of furans with olefins, and the alkylation reaction of benzene/toluene with methanol occurring during the coupling conversion of MF and methanol. The reaction conditions for maximizing the synergistic effect were a methanol to MF molar ratio of 2 at 550 °C. Moreover, the comparative study of the coupling conversion of different bio-derived furans (MF, 2,5-dimethylfuran (DMF), furfural (FF) and furfuryl alcohol (FA)) and methanol were also considered in this study. The coupling conversion of DMF and methanol exhibited maximum yields of aromatics, olefins and a minimum yield of coke, suggesting that DMF is the best candidate of bio-derived furans for aromatic production in the coupling conversion of bio-derived furans and methanol.
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CATALYSIS COMMUNICATIONS
·
2012
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IF 2.986
Linping Sun,Xinwen Guo,Guang Xiong,Xiangsheng Wang
The ethylation of coking benzene with ethanol over nano-sized ZSM-5 zeolites modified with Y 2 O 3 , La 2 O 3 and CeO 2 was investigated in a fixed-bed reactor. Nano-sized ZSM-5 zeolite modified with Y 2 O 3 was more stable than the other two samples during the reaction. The results from NH 3 -TPD, Py-IR, and TG-DTA show that the strong Brønsted acid sites were eliminated, consequently suppressing coke deposits during the reaction. Combined with the results from 1 H NMR and 129 Xe NMR spectra, it is concluded that the hydrated Yttrium ions with small size reached deep location in zeolite channel.
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NEW JOURNAL OF CHEMISTRY
·
2024
·Vol. 48
·期 35
·15512-15523
·
IF 2.7
Sen Fu,Hanxu Guo,Hong Yuan
A nano-ZSM-5 zeolite having a hierarchical pore structure was synthesized using L-lysine as a mesopore template and growth inhibitor. The effects of the L-lysine/Si and Si/Al molar ratios on the morphology and pore structure of the zeolite were studied. The products were characterized by scanning electron microscopy, transmission electron microscopy and N2-Brunauer–Emmett–Teller surface area analysis. These assessments showed that the particle size of the ZSM-5 zeolite could be reduced to 60 nm with a surface area as high as 395 m2 g−1 and a high density of mesopores. These zeolites were applied to the catalytic pyrolysis of oleic acid in a fixed-bed reactor to generate benzene, toluene and xylenes (BTX). At a reaction temperature of 500 °C, the catalyst having L-lysine/Si and Si/Al ratios of 0.4 and 30, respectively, gave a BTX yield of 27.4 wt%. This yield decreased with increases in the Si/Al ratio whereas varying the L-lysine/Si ratio did not produce a specific trend. The spent catalyst was characterized by thermogravimetric analysis and exhibited superior anti-coking ability and longer catalytic lifetime compared with a standard ZSM-5 zeolite.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Xin Zhou,Mingyang Ma,Ruhan Zhang,Xinru Song,Wenjie Li,Jiachen Jiang,Junlin Xie,Xiaoqiang Li,Li Cai,Xueqin Sun,Pijun Gong
This paper introduces a novel approach of encapsulating Pt nanoparticles within the pores of a molecular sieve. By comparing the dispersion, reducibility and surface acid sites, the effect of the combination of molecular sieves and Pt particles on the catalytic performance of toluene was studied. The findings demonstrate that Pt nanoparticles were encapsulated within the molecular sieve framework of ZSM-5 molecular sieves using an in-situ synthesis method, exhibiting remarkable catalytic activity towards toluene oxidation (T 90 =172 ℃). Mainly due to the spatial confinement of the ZSM-5 molecular sieve framework reduces the size of Pt nanoparticles, enhances their dispersion of the Pt@ZSM-5 catalysts. In addition, the space separation effect of ZSM-5 on Pt metal enhances their interaction and promotes the valence state conversion of Pt species. It leads to a large number of acid sites and oxygen vacancies in the catalyst, which improves the adsorption and migration of toluene, thereby improving the catalytic activity. This study will provide valuable insights into the preparation of new nanocatalysts and the catalytic treatment of toluene.
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ENERGY
·
2025
·
IF 9.4
Xin Li,Jie Zhu,Shengli Niu,Yue Zheng,Yang Xu
Biodiesel, known for its low carbon emissions and renewability, offers a promising alternative to fossil diesel. Support loading and additive modification are effective strategies for synthesizing high-performance heterogeneous catalysts. This study modified ZSM-5 zeolite with the addition of divalent barium ions and tetravalent cerium ions to develop the novel acid-base dual-activity Ba-Ce/ZSM-5 catalyst for biodiesel production from the acidified palm oil through transesterification. Characterization results show that the synergistic loading of the divalent barium ions and the tetravalent cerium ions generates snowflake-like particles on the multi-porous ZSM-5 surface and increases the density of catalytic active sites. Compared to the pure ZSM-5, the Ba40-Ce15/ZSM-5 catalyst exhibits nearly a five-fold increase in average pore size and forms the hierarchical pore structure. This modification reduces the diffusion resistance of triglycerides during transesterification. The catalyst retains excellent activity even in the presence of 5.00 wt% free fatty acids and moisture. With optimization by Response Surface Methodology with Box-Behnken Design (RSM-BBD), the maximum biodiesel yield of 97.48 % is achieved at the alcohol-to-oil molar ratio of 14.95 : 1, reaction temperature of 149.6 °C, catalyst amount of 6.73 wt%, and reaction duration of 2 h. Compared to previously reported catalysts, the Ba40-Ce15/ZSM-5 catalyst exhibits superior performance in increasing biodiesel yield while offering greater cost-effectiveness.
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