Journal of Environmental Chemical Engineering
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2025
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IF 7.2
YiRong Yao,Bing Xing,Jianbing Chen,YanLun Ren,YuJia Ma,Ying Zhang,Li Zhang
This study proposes an advanced method to tackle CO 2 emissions by enhancing solid acid catalysts, aiming to reduce the high energy consumption and low economic efficiency typically associated with chemical absorption processes. The research involves modifying commercial HZSM-5 zeolites through Cu ion exchange, with the optimal performance observed at a Cu ion content of 2.86 % and a Cu salt concentration of 0.2 M. This modification significantly minimizes the loss of copper ions—a common issue in the impregnation method—resulting in a 76.62 % reduction in the loss of active components. To further improve CO 2 gas-liquid mass transfer, mesoporous MCM-41 zeolites were introduced. Experimental results demonstrate that, at a regeneration temperature of 86°C and a mass ratio of 2:1 for HZSM-5 to MCM-41, the combined catalyst achieves a 61.28 % reduction in relative heat duty compared to the blank sample. Moreover, the energy consumption is 12.33 % and 16.45 % lower than that of HZSM-5 and MCM-41 used individually. Characterization analysis reveals that, under comparable acidic active site densities, catalysts with superior physical pore structures exhibit enhanced catalytic performance. The introduction of mesoporous structures notably improves the bidirectional mass transfer efficiency between carbamate macromolecules and CO 2 molecules. This work successfully demonstrates the synergistic effect of combining Cu ion-modified HZSM-5 zeolites with mesoporous MCM-41, leveraging the abundant active sites of HZSM-5 while harnessing the enhanced mass transfer properties of MCM-41.
研究领域:
化学工程
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环境科学
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高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2021
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IF 5.541
Xiaohua Li,Shengnan Ge,Shanshan Shao,Zhichao Lv,Xianliang Xiang,Yixi Cai
In order to promote the production of hydrocarbons in the catalytic pyrolysis of rape straw, a core-shell catalyst fabricated by external recrystallization method was employed. The composite catalyst HZSM-5@MCM-41 was prepared by varying the mass ratio of template and HZSM-5 (THR), and the effect of zeolite acidity and mesoporosity on the production of hydrocarbons was analyzed. A final pyrolysis temperature of 500 °C was suitable to obtain high yield of hydrocarbons over composite catalysts. Compared with ZSM-5 with a favorable pyrolysis temperature of 550 °C, a lower pyrolysis temperature meant a more efficient process, which may be related closely to the good diffusion of large-sized pyrolysis vapors over HZSM-5@MCM-41 catalysts. In addition, the highest yield of monocyclic aromatic hydrocarbons obtained over HZSM-5@MCM-41 with THR of 1 was 11.43 wt.%, which was boosted by 2.5 times compared with HZSM-5. A proper THR was suitable to fabricate a core-shell catalyst with excellent crystallinity, acidity and mesoporosity, and resulting in a high yield of hydrocarbons. Furthermore, the core-shell catalyst presents less formation of graphite-like coke, which indicated the easier removal of coke. Therefore, the composite HZSM-5@MCM-41 catalysts were more appropriate for upgrading of pyrolysis vapors for hydrocarbons.
研究领域:
能源与环境科学
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催化化学
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高影响因子
Catalysis Science & Technology
·
2018
·Vol. 8
·期 16
·4241-4256
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IF 5.365
Xiaochao Xian,Chao Ran,Peng Yang,Yirong Chu,Shuo Zhao,Lichun Dong
The effect of the acidity of HZSM-5/MCM-41 hierarchical zeolite on its catalytic performance in the supercritical catalytic cracking of n-dodecane was investigated by controlled ion exchange with NaCl solution under ultrasonic conditions. XRD and nitrogen adsorption–desorption results showed that the crystal and porous properties were not affected, while NH3-TPD, the probe reaction of n-hexane cracking and temperature-programmed surface reaction (TPSR) of n-dodecane demonstrated that strong Brønsted acid sites were replaced by Na+ (weak Lewis acid sites) to different extents with varying concentrations of NaCl solution. Although the initial conversion of n-dodecane during the supercritical catalytic cracking was slightly reduced, its stability was greatly enhanced by ion exchange. An ultrastable catalyst with no obvious deactivation within 3 h of time on stream (TOS) was obtained by ion exchange with 0.8 M NaCl solution. A mechanism describing the role of the acid sites residing in both micropores and mesopores of the hierarchical catalyst was proposed based on coke analysis.
研究领域:
化学工程
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催化科学
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高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
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2014
·Vol. 16
·期 12
·1-11
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IF 2.278
Sang Yu,Jiao Qingze,Li Hansheng,Wu Qin,Zhao Yun,Sun Kening
A series of HZSM-5/MCM-41 composite molecular sieves (HZM-Ns ( x )) were prepared by employing nano-ZSM-5 zeolites with the SiO 2 /Al 2 O 3 ratios ( x ) of 50, 100 and 150 as the source. These materials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, N 2 adsorption–desorption measurement, and NH 3 temperature-programmed desorption. The catalytic cracking of endothermic hydrocarbon fuels over the HZM-Ns with n -decane as model was evaluated at atmospheric pressure and 500 °C. The effect of the parent zeolite, mesopore and SiO 2 /Al 2 O 3 ratio on the structure, acidity, and catalytic performance of HZM-Ns was investigated. The HZM-Ns exhibited a skeletal matrix with nano-sized HZSM-5 particles (200–300 nm) with a controllable acidity well dispersed in and microporous–mesoporous hierarchical pores. The mesoporous structure improved the diffusion of the reactants and products in the pores, and the HZSM-5 nanoparticles uniformly dispersed in the MCM-41 matrix supplied a proper acidity, shorter channels, and a higher specific surface area for reaction. These resulted in a high catalytic activity, a high selectivity to light olefins and a long lifetime for n -decane catalytic cracking. The HZM-N (150) exhibited the excellent conversion, a high selectivity to light olefins and a long lifetime due to low diffusion resistance, high specific surface area, and appropriate acid distribution and strength, with the increasing SiO 2 /Al 2 O 3 ratio.
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高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2021
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IF 5.541
Xiaohua Li,Jinlong Yan,Shanshan Shao,Shengnan Ge,Zhichao Lv,Yixi Cai
A method of template removal by direct non-thermal plasma (DNTP) system for the synthesis of HZSM-5/MCM-41 meso-micropore composite catalyst was proposed for the production of aromatic hydrocarbons by catalytic pyrolysis of rape straw. It was revealed most of the template on the catalyst was removed by oxidizing substances such as ozone produced by DNTP. During DNTP treatment, the removal effect of the template was greatly affected by the oxygen flow rate . Also, the catalyst structure was bombarded by high-energy electrons obtained by DNTP treatment, and the physicochemical property of the synthetic composite catalysts was treated quite different from that obtained by calcination method. Under the treatment condition of 22 kV-2 L/min, the BET surface area was boosted significantly by 29.91% and the amount of acid sites was boosted by 37.71%, the yield of MAHs reached 10.57 wt%. Generally, not only the template can be effectively removed by DNTP treatment, but also the physicochemical property of meso-micropore composite catalyst can be improved, and thus promoted the catalytic performance for monocyclic aromatic hydrocarbons. Therefore, DNTP is an effective technology for removing template and the catalytic performance can be efficiently improved.
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高影响因子
JOURNAL OF THE ENERGY INSTITUTE
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2025
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IF 6.2
Ziwen Zhao,Hong Tian,Zhengye Chen,Zhangjun Huang,Shan Cheng,Siying Liu
This study employed torrefied wheat straw (260°C) as feedstock to synthesise a bifunctional metal-modified composite zeolite catalyst through alkali treatment (NaOH), dual metal loading (Fe and Ni), and hierarchical MCM-41 construction. Catalytically assisted pyrolysis behaviour was investigated using a tube furnace and Py-GC/MS system, evaluating the effects of pyrolysis temperature and catalyst/feedstock mixing ratio on product distribution and bio-oil composition. Results indicate that at a catalyst/feedstock ratio of 3:2, bio-oil yield peaked at 28.41% at 500°C, concurrently achieving a maximum monocyclic aromatic content of 66.36%. Elevating pyrolysis temperature promoted aromatic formation while significantly suppressing oxygenated compounds; notably, phenolic components decreased by 13.94% at 500°C, indicating the 1Ni1FeHR@M catalyst's potent deoxygenation capability. Further optimisation of the catalyst/feedstock blending ratio revealed that a 3:2 ratio yielded the highest combined bio-oil and monocyclic aromatic hydrocarbon production (18.62%), confirming this catalytic strategy effectively shifts the product distribution towards higher-value hydrocarbon fuels.
研究领域:
生物能源
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催化
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热解
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可再生能源
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生物质转化
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高影响因子
危险品化学品经营许可证（带存储）