MICROPOROUS AND MESOPOROUS MATERIALS
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2019
·
IF 4.182
Kai Gao,Qing Wang,Xuexun Du,Qinglian Wei,Yongmin Huang
Dimethylamine (DMA), which is mostly generated in fine chemical industry, has enormously threatened the public health, therefore should be eliminated from water efficiently. Superior to any other methods to remove DMA, adsorbing it by sorbent could avoid the generation of secondary pollution. Among all the sorbents employed in this study, low Si/Al ratio Beta zeolite synthesized without organic template exhibits the highest performance of adsorbing DMA from water. When the transition-metal cations were introduced by ion-exchange, the adsorption of DMA was enhanced. Subsequently, the saturated adsorbent was heated in air condition, detection results of the off-gas indicated that nearly all of the DMA adsorbed was oxidized and negligible harmful by-product was produced. Beta zeolite adsorption coupled with catalytic oxidation could eliminate DMA efficiently and environmental friendly which has wide application prospects in waterworks.
研究领域:
环境科学
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化学工程
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产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2017
·
IF 9.446
Ling Zhang,Long Chen,Yaobin Li,Yuexin Peng,Fang Chen,Liang Wang,Changbin Zhang,Xiangju Meng,Hong He,Feng-Shou Xiao
For human health and environmental protection, removal of formaldehyde (HCHO) has become a hot topic, and completely catalytic oxidation at room temperature has been identified as one of the efficient routes for solving this problem. Recently, it has been reported that zeolite-supported Pt catalysts are active for HCHO oxidation at low temperatures, but they are still unable to completely oxidize HCHO at room temperature. To enhance the activity, it has been suggested to increase the Pt dispersion and acidic density in the zeolite-supported Pt catalysts. We therefore chose Al-rich Beta as a zeolite support because abundant aluminum species in the zeolite framework are advantageous for increasing acidic density through ion-exchange of protons and for improving Pt metal dispersion through the metal-zeolite interaction by increasing the negative charge of the zeolite framework with positively charged metal ions. As we expected, the Al-rich Beta zeolite supported platinum catalyst is very active, giving complete oxidation of HCHO at room temperature. To the best of our knowledge, this is the first time the complete oxidation of HCHO at room temperature over a zeolite-supported noble metal catalyst has been realized. In addition to its extraordinary activity, this catalyst is also very stable and selective. The strategy of designing zeolite-supported noble metal catalysts might offer an alternative way to develop highly efficient heterogeneous catalysts for the removal of air pollutants.
研究领域:
环境科学
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催化化学
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产品关联
DOI
高影响因子
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
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产品关联
DOI
高影响因子
CATALYSIS LETTERS
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2024
·
IF 2.3
Dong Wenjie,Cai Ao,Wu Sui,Qi Beimeng,Dai Zhixi
A porous Sn–Er–Beta zeolite catalyst was rapidly prepared by introducing Sn source with water bath method and Er source with solid-state ion exchange method. When adding 180 mg catalyst, 225 mg glucose and 10 mL water into a reaction kettle at 200 °C for 2 h, the yield of lactic acid can reach 71.2%. After being recycled 5 times, the lactic acid yield of the catalyst can still reach 45.3%. The physical and chemical properties of Sn–Er–Beta zeolite were characterized, and it was confirmed that the catalyst had a multi-stage pore structure, with Sn and Er elements existing in the zeolite skeleton. Among them, the increase of Lewis acidity, Brønsted acidity and special strong alkaline sites of Sn–Er–Beta zeolite caused by the introduction of Sn, and the Lewis acidic sites are further increased after the introduction of Er. The combination of Sn and Er obviously improves the catalyst’s capability to catalyze glucose and fructose to produce lactic acid. This provides an important reference value for the directional catalytic process of sugars. Graphical abstract
研究领域:
化学工程
·
催化科学
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产品关联
DOI
高影响因子
ENVIRONMENTAL RESEARCH
·
2024
·
IF 7.7
Meng Xia,Kaihao Xu,Shuai Zhang,Chengxue Zhang,Xiaocong Wang,Jiqun Li
Pyrolysis technique is considered to have great potential in the remediation of petroleum-contaminated soil, but it still has difficulties such as high energy consumption for the degradation of complex petroleum hydrocarbons and the deterioration of soil quality after treatment. In this study, the low-temperature rapid catalytic pyrolysis was realized using Beta zeolite to assist in remediating weathered petroleum-contaminated saline-alkali soil. Under the action of Beta zeolite, the removal efficiency of petroleum hydrocarbons reached 81% after pyrolysis treatment for 10 min at 250 °C, which was reduced to regulatory standard. The pyrolysis behavior and mechanism revealed that the addition of Beta zeolite effectively reduced the activation energy of C-C and C-O bonds cleavage in petroleum hydrocarbon macromolecules due to the strong acidity of Beta, meanwhile the quality of recovered oil from pyrolysis was improved. Additionally, the analyses of soil physicochemical property indicated that the harmless graphitic C generated from the degradation of petroleum hydrocarbons increased the organic matter in the soil, and the addition of Beta zeolite enhanced soil water retention capacity and reduced the soil alkalinity, thus improving the ecological function of saline-alkali soil. This study provides a new strategy for the removal of organic pollutants under special soil media conditions.
研究领域:
环境科学
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土壤修复
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产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2023
·
IF 8.6
Zhipeng Qie,Zhaoqi Ji,Huan Xiang,Xinhan Zhang,Abdullah Alhelali,Lan Lan,Hassan Alhassawi,Guangbo Zhao,Xiaoxia Ou,Xiaolei Fan
Adsorption capacity of zeolitic adsorbents for organic pollutants can be affected severely under humid conditions and/or in aqueous systems. This study presents the development of hydrophobic Beta zeolites using a microwave-assisted post-synthetic treatment method (i.e., microwave-assisted chelation, MWAC) for adsorption removal of organics (benzene and phenol as the models) in aqueous systems. MWAC treatment enabled the dealumination of Beta zeolites in only one minute whilst increasing its hydrophobicity. Based on the characterization data, the mechanism for the hydrophobization of Beta zeolite was proposed. The influence of hydrophobicity, porosity and the property of organic molecules on adsorption behaviours were systematically studied, showing that the most hydrophobic Beta zeolite presented the highest benzene adsorption capacity per surface area of 2.87 × 10 −3 mmol/m 2 (at 1.0 g/L initial concentration). TGA and multi-cycle regeneration/adsorption experiments were employed to assess the regeneration and reusability of the adsorbents, and the results suggested that the modified Beta zeolites could be regenerated easily with the preserved physiochemical properties and adsorption capacity. The developed method and the associated zeolitic materials could be developed further for making high-performance hydrophobic zeolitic adsorbents for applications in organics removal from aqueous media.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2021
·
IF 3.171
Shuo Li,Jianlin Cao,Xiang Feng,Yupeng Du,De Chen,Chaohe Yang,Wenhua Wang,Wanzhong Ren
Elucidating the confinement effect harbours tremendous significance for isobutane alkylation with C 4 olefin . Herein, the confinement effect over zeolite catalysts was elucidated by combining DFT calculations, experiments (using the novel Beta zeolite exposing only external surfaces (Beta-E) and conventional Beta-I zeolite with both external and internal surfaces) and multi-techniques ( e . g ., TGA-DTG, HRTEM, SEM and XRD). It is found that the main active sites for C 4 alkylation reaction are located on internal surface rather than external surface. On the external surface, the hydride transfer reaction does not occur because the H-shared intermediate cannot be formed without the confinement effect. Moreover, the external surface has stronger selectivity for C 4 olefin adsorption than isobutane, leading to enhanced oligomerization reactions. Therefore, the suitable micropore with confinement effect is essential for zeolite-catalyzed C 4 alkylation. The atomic-scale insights of this work are of great referential importance to the design of highly effective zeolite catalyst.
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
CHEMICAL ENGINEERING JOURNAL
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2025
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IF 13.2
Xiaolong Liu,Jiahe Sun,Shuo Li,Kaixuan Yang,Ting Su,Hongying Lü,Zhiguo Zhu
Sn-containing zeolite catalysts exhibit the unique feature of selectively activating carbonyl groups in organic compounds, which demonstrate relatively high activity and selectivity in the Baeyer-Villiger (B V) oxidation of aldehydes or ketones using H 2 O 2 as the oxidant. However, the influence of diffusion property and trace water on the ε-caprolactone selectivity as targeted product in the cyclohexanone's B V oxidation system with the green oxidant of aqueous H 2 O 2 remains unclear. To address this, three kinds of Sn-Beta zeolites are prepared by interzeolite transformation, structural reconstruction, and post-synthesis method to establish structure-property relationships. The physicochemical property and Sn coordinated state are investigated in detail. The existence of trace water in the reaction system negatively affects the conversion and product selectivity by competitive adsorption of water with reaction substrates and facilitated hydrolysis of ε-caprolactone, respectively. DFT calculation implies that kinetics dominates the conversion of cyclohexanone → ε-caprolactone → 6-hydroxycaproic acid. The structure-property relationship indicates that the cyclohexanone conversion and ε-caprolactone selectivity are closely related to the adsorption amounts of substrates and the diffusion performance of products, respectively, over Sn-Beta zeolite catalysts. Finally, the reusability and deactivation mechanism are analyzed. This study aims to provide guidance for designing efficient stannosilicate zeolite catalysts for B V oxidation through precisely modulating the zeolite's diffusion property.
研究领域:
催化化学
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材料科学
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有机化学
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产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2017
·
IF 4.636
Yuexin Peng,Ling Zhang,Long Chen,Dingzhong Yuan,Guoxiong Wang,Xiangju Meng,Feng-Shou Xiao
Catalytic combustion of toluene has been widely investigated due to importance of abatement of volatile organic compounds (VOCs), and in this work we have successfully prepared highly efficient heterogeneous catalysts for toluene combustion by impregnation of manganese oxides with Al-rich Beta zeolites (Beta-SDS) with H-form (MnO x /H-Beta-SDS) and K-form (MnO x /K-Beta-SDS) as well as pure siliceous Beta zeolite (MnO x /Si-Beta). Catalytic tests show that these zeolite-supported catalysts have higher activities than alumina-supported manganese oxides (MnO x /Al 2 O 3 ). By comprehensive consideration of reducibility, adsorbed oxygen species, and lattice oxygen species in the catalysts, it is shown that the adsorbed oxygen species play more important roles than others for the catalytic activity. The good catalytic performance and understanding of active sites over the MnOx/H-Beta-SDS might be helpful for preparation of catalysts in VOCs abatement.
研究领域:
环境科学
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催化化学
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产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 10
·5556-5562
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IF 7.443
Chunyu Chen,Qinming Wu,Fang Chen,Ling Zhang,Shuxiang Pan,Chaoqun Bian,Xiaoming Zheng,Xiangju Meng,Feng-Shou Xiao
The removal of volatile organic compounds is an important aspect of sustainability and environmental protection. Catalytic oxidation is one of the most efficient routes to achieve this. The K+ form of an aluminium-rich Beta zeolite-supported Pt nanoparticle (2.2 nm) [Pt/KBeta-seed-directed synthesis (SDS)] catalyst is very active for the low-temperature catalytic removal of toluene and results in full conversion at a much lower temperature than a conventional KBeta-supported Pt nanoparticle (Pt/KBeta-TEA) catalyst. The higher activity of the Pt/KBeta-SDS catalyst compared with the Pt/KBeta-TEA catalyst is related to the advantages of the higher K+ content and fewer terminal silanol defects in the KBeta-SDS catalyst than in the KBeta-TEA catalyst. The higher K+ content is helpful for the formation of more Pt0 species, and both the higher K+ content and the lower number of terminal silanol defects are favourable for the adsorption of toluene, as evidenced by XPS and the toluene-TPD profiles. More importantly, the Pt/KBeta-SDS catalyst shows very stable activities in the presence of H2O and CO2 in the feed gases. The combination of this extraordinary activity and excellent stability in the catalytic removal of toluene over the Pt/KBeta-SDS catalyst are important for future environment protection.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
DALTON TRANSACTIONS
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2020
·Vol. 49
·期 21
·7258-7266
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IF 4.174
Guanqun Zhang,Yaqi Fan,Ju Huang,Lijin Wang,Chengguang Yang,Meng Lyu,Haiming Liu,Yanhang Ma
The increasing demands for catalysts with improved accessibility to reactants call for a rational synthesis of nanosized zeolites. Herein we developed a facile approach for highly crystalline MFI-type (Silicalite-1 and ZSM-5) and beta zeolites with variable Si/Al ratios and high yield. This was achieved by kinetically decoupling the nucleation from the growth process of the zeolites in a highly concentrated gel system via a temperature-staged treatment. The carefully controlled low-water environment ensures only nucleation in stage I (aging), and hence the generation of abundant nuclei for the subsequent rapid crystallization within a self-confined space at stage II (growth). The method, without using expensive templates or additives, allows the syntheses of nanosized, well-isolated ZSM-5 (Si/Al = 100–∞, 36–88 nm, yield >85%) and Beta (Si/Al = 25–100, 21–66 nm, yield >95%). The ultra-small crystal size endows ZSM-5 zeolites with good catalytic activity, product selectivity and remarkably longer lifetime in methanol conversion reactions.
研究领域:
化学工程
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材料科学
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Yibo Qin,Longfei Chen,Lixia Ge,Yanfeng Zhu,Wanting Li,Xinxin Cao,Tianchang Wang,Jiong Li,Wei Han,Xinqing Chen
Hydrogen spillover plays a crucial role in heterogeneous catalysis, significantly enhancing the activity of catalysts. However, the promotion mechanism of hydrogen spillover on non-reducible oxide supports (such as zeolite) is rarely reported. Herein, we prepared Ru@Beta sample by in-situ approach, effectively encapsulating Ru species into Beta zeolite. Additionally, three samples (Ru/SiO 2 , Ru@Naβ, and Ru@Hβ) with different hydrogen spillover effect were prepared. The optimal concentration of Ru was 0.5 wt%, and the Ru@Hβ sample with the strongest hydrogen spillover has 100 % conversion rate of N-ethylcarbazole (NEC) and 98 % selectivity towards to 12H-NEC. In contrast, the Ru/SiO 2 with weak hydrogen spillover has only 89.5 % conversion rate and 28.9 % selectivity of 12H-NEC. Notably, the Ru@Hβ can still completely convert NEC even after 7 cycles, thereby exhibiting its remarkable activity and stability. Various characterizations (HAADF-STEM, XPS, EXAFS, in-situ DRIFT, and H 2 -TPD) indicate the superior catalytic performance of Ru@Hβ with strong hydrogen spillover effect, originating from the presence of more hydroxyl (–OH) and Brønsted acid on the surface, while Lewis acid act as hydrogen acceptors and NEC hydrogenation sites. This work not only expands our understanding of the hydrogen spillover, but also paves the way onto the potential applications in heterogeneous catalysis for efficient hydrogenation.
研究领域:
催化化学
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材料科学
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能源存储
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）