CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2024
·Vol. 40
·期 6
·1245-1255
·
IF 3.1
Bo Shuang,Wang Tianlong,Lv Tianming,Wu Huifang,Feng Ziyi,Miao Lei,Feng Zhaochi,Ren Limin,Meng Changgong
ERB-1 zeolite emerges as a key bridging material for crafting heteroatom-containing MWW for versatile catalytic applications. In this study, we developed a solvent-free strategy facilitated by high-temperature condition and seed assistance, streamlining the synthesis of ERB-1 zeolite. This novel approach not only significantly reduces the growth time to 12 h compared to the conventional 168-h hydrothermal synthesis but also enhances product yield while minimizing waste generation. Benefiting from the platelet seeds and the grinding force, a distinct non-classical growth pathway, involving nanoparticle attachment, epitaxial growth, anisotropic assembly, and crystallization, was observed in the solvent-free synthesis. Through heteroatom substitution, pillared Sn-MWW was successfully prepared, exhibiting remarkable stability and catalytic performance in the Bayer-Villiger oxidation reaction of 2-adamantanone. Our findings present a simple and cost-effective way for rapid synthesis of MWW zeolite, with implications extending to diverse catalytic applications.
研究领域:
材料化学
·
催化化学
·
纳米材料科学
·
多孔材料
·
绿色合成
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2021
·
IF 5.706
Juan Ye,Chenyu Chen,Ying Zheng,Dan Zhou,Yunzhen Liu,Denglong Chen,Liufang Ni,Gang Xu,Fanan Wang
The selective one-pot synthesis of lactic acid (LA) from cellulose, and further the raw biomass, on heterogeneous catalysts is the key point for the development of biorefinery technology. Herein, we reported an yttrium (Y) modified siliceous Beta zeolites catalyst via two-step post-synthesis for highly efficient conversion of cellulose to LA. Under condition of 220 °C and 2 MPa N 2 , the cellulose could be transformed to LA with a yield of 49.2 % within 30 min, and the substrate can be extended to various raw biomass. It was demonstrated that the dealumination and modification of Y can efficiently modulate the acidity on the surface of zeolite. The dehydration products HMF and other derivatives were suppressed, and the yield of LA was correlated in line with the acid amount, which were attributed to the increased Lewis acidity originated by Y incorporation. These results contribute to the development of the green and efficient synthesis of bio-chemicals.
研究领域:
生物化学
·
催化化学
·
可再生资源
✓ 已验证
DOI
高影响因子
KOREAN JOURNAL OF CHEMICAL ENGINEERING
·
2016
·Vol. 33
·期 7
·2097-2106
·
IF 1.408
Bai Ting,Zhang Xin,Liu Xiling,Chen Tengfei,Fan Wentao
A series of HZSM-5 catalysts were synthesized by different methods. The physicochemical properties of the HZSM-5 catalysts were characterized by XRD, SEM, N2 isothermal adsorption-desorption, NH3-TPD, Py-IR and TGA, respectively. The results indicated that different preparation conditions lead to different morphologies, textures and the distribution of acid sites. The nanosized HZSM-5 catalysts exhibited better catalytic reactivity and coke capacity than the micro-sized HZSM-5 because nanosized HZSM-5 had larger specific surface area, higher pore volume, more exposed channels and more accessible acid sites. The large particles of NZ-3 in a reasonable range and the smooth surface were conducive to product diffusion; therefore, NZ-3 exhibited higher specific propylene yield and stability than the other nanosized catalysts. The moderate density and distribution of acid sites on NZ-3 also favored the formation of propylene.
研究领域:
化学工程
·
催化科学
✓ 已验证
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
MICROPOROUS AND MESOPOROUS MATERIALS
·
2019
·
IF 4.182
Aihu Feng,Yang Yu,Le Mi,Yunzhen Cao,Yun Yu,Lixin Song
In this work, the hierarchical Y zeolites are firstly obtained by etching NaY zeolites with different NH 4 HF 2 solutions. The morphology and microstructure, toluene adsorption property of as-prepared hierarchical Y zeolites are characterized. The results demonstrate that the mesoporous number and size, the n(SiO 2 )/n(Al 2 O 3 ) value of hierarchical Y are increased with NH 4 HF 2 concentration. The 0.3M NH 4 HF 2 -etched NaY exhibits satisfactory crystallinity, suitable mesoporous content and better toluene adsorption performance. The NH 4 HF 2 -etched NaY is an excellent material for pressure swing adsorption. Furthermore, the synthesis mechanism of hierarchical Y has been elaborately demonstrated. The synergistic effect of H + and F − is beneficial to dealumination as well as the introduction of mesoporous. The NH 4 HF 2 ionizes into positive H + and negative F − at a very slow rate, which avoids the concentration of H + and F − going up suddenly. Under the circumstances, the dealumination reaction between NH 4 HF 2 and NaY zeolites is more sustained and mild, and the crystallinity of hierarchical Y zeolites is higher than that of the HCl/NH 4 F-etched or HF/NH 4 F-etched NaY. This work presents an effective method to synthesize the hierarchical Y zeolites.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
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
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Energies
·
2022
·Vol. 15
·期 7
·2620
·
IF 3.252
Fanjing Wei,Xiaoqin Guo,Weiren Bao,Liping Chang,Junjie Liao
The ultra-deep removal of thiophene is essential for the conversion of coke oven gas to methane and metal modified Y zeolite has excellent thiophene adsorption capacity. The effects of temperature on chemisorption between metal modified Y zeolite and thiophene and the reductive gases in coke oven gas on the thiophene adsorption performance still remains ambiguous. To address the aforementioned aims, series of NaMY (M = Ce, Ni, Zn and Ag) were prepared via ion-exchanged with Na+of NaY, and two comparable sets of thiophene adsorption evaluation were conducted in a fixed bed reactor: (1) NaY and NaMY were evaluated at different temperatures in simulated coke oven gas, and (2) NaCeY was evaluated in N2and different reductive atmospheres. The results show that NaNiY, NaZnY and NaAgY could adsorb thiophene via π-complexation, however, NaCeY mainly through S-Ce bond. Π complexation becomes weak above 150 °C, and the strength of S-Ce bond varies little when the temperature rises to 250 °C. Compared with that of other sorbents, the breakthrough adsorption capacity for thiophene (Qb-thiophene) of NaAgY reaches the highest 144 mg/g at 100 °C, but decreases sharply when temperature rises to 200 °C. NaCeY has relatively low variation inQb-thiophenefrom 100 °C to 200 °C. Moreover, Ce(IV) in NaCeY is more favorable for thiophene adsorption than Ce(III) in coke oven gas and the presence of H2and CO would reduce the desulfurization activity of NaCeY. For the industrial utilization of thiophene ultra-deep removal, NaAgY has an excellent potential below 150 °C, while NaCeY with more Ce(IV) has a good prospect at 150–250 °C.Keywords:coke oven gas;thiophene;adsorption;Y zeolite;metal modification
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
DESALINATION
·
2024
·
IF 8.3
Wen Guo,Zixin Lin,Kun Jiang,Hao Li,Xiangfeng Liang,Weizhong An,Huizhou Liu,Haiyan Luo,Haoyu Yao
The extraction of uranium from seawater is not only crucial from a strategic standpoint but also poses significant technical challenges. In this work, a series of novel bifunctionalized mesoporous silicas were prepared through a straightforward method, utilizing the structural characteristics of SBA-15 and synergistic effect of functional groups. The impact of pH value, initial uranium concentration, temperature, and duration on uranium adsorption was investigated through a series of batch experiments. The bifunctional modified SBA-15 demonstrated rapid uranium adsorption, which was a spontaneous endothermic reaction and conformed to the pseudo-second-order model. Thereinto, SBA-15 modified with aldoxime and amino group (SBA-15-SAO-N) exhibited the best uranium adsorption performance, with a maximum adsorption capacity of 701.85 mg·g −1 at 298 K and pH 6, an increase of 146 % compared to SBA-15-SAO. SBA-15-SAO-N exhibits excellent U/V selectivity (selectivity coefficient of 30) in the coexistence of U and V solutions, and it still maintains high adsorption capacity after five adsorption-desorption cycles. In actual seawater conditions, the adsorption capacity of SBA-15-SAO-N was 135.26 μg·g −1 . By combining DFT calculations and characterization, the coordination model and interaction energy between functional groups and uranyl were elucidated, revealing that introducing bifunctional groups can enhance the binding strength of adsorbents to uranium and form more stable complexes, thereby improving adsorption capacity and selectivity. These results indicate that bifunctional modified mesoporous silica offers a promising strategy for recovering uranium resources from seawater.
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
CHEMICAL PHYSICS LETTERS
·
2024
·
IF 2.8
Xu Gao,Aihu Feng,Le Mi,Yang Yu,Yun Yu
Adsorption is one of the most effective methods for controlling the concentration of VOCs pollution. In this work, the hierarchical NaY zeolites with size-controlled mesopores in the range of 2–5 nm are obtained via NH 4 HF 2 -etching and surfactant-templating process. By using the different cationic surfactant (C n TAB), we fabricate the surfactant-templated zeolite with controllable mesopores, and improve its adsorption capacity for toluene. In addition, the modified zeolite’s hydrophobicity is enhanced, and it maintains a high adsorption capacity in a complex humid environment.
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
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2015
·
IF 1.098
Guo Lin,Qiang Zhuang,Qun Cui,Haiyan Wang,Huqing Yao
Co-crystalline zeolite FAU/LTA-0 was synthesized by hydrothermal method from lithium slag. To make the most of excess silicon and alkali sources in mother liquid derived from FAU/LTA-0, zeolite FAU/LTA-1b was synthesized in the same method with the use of mother liquid by adding a certain amount of aluminum source. Influences of different adding ways of aluminum source and recycling dosages of mother liquid on synthesis of zeolites FAU/LTA with mother liquid were investigated. The phase, microstructure and thermostability of FAU/LTA-0 and FAU/LTA-1b were characterized by XRD , SEM and TG-DTA. The calcium and magnesium cation exchange capacities (CECs) of the zeolites were determined. The results have shown that co-crystalline zeolite can be synthesized with the use of mother liquid by adding aluminum source after 2 h of reaction. Compared with FAU/LTA-0, the crystal twinning structure of FAU/LTA-1b became weaker, the grain size was smaller, and the thermostability was better. With a lower dosage of mother liquid, the content of P-type impurity in product decreased significantly, and the content of LTA phase increased. The reuse rate of mother liquid can reach 48%. The CECs of FAU/LTA-1b-150 can reach 343 mg CaCO 3 ·g − 1 and 180 mg MgCO 3 ·g − 1 , showing more excellent adsorption capacities than FAU/LTA-0 and commercial zeolite 4A. The full recycling use of mother liquid to synthesize zeolite FAU/LTA which can be applied for detergent not only improves resource utilization but also reduces production cost.
研究领域:
材料科学
·
环境工程
✓ 已验证
DOI
高影响因子
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
·
2022
·Vol. 101
·期 3
·1591-1601
·
IF 2.5
Renjie Deng,Yao Tian,Huajie Liu,Weiwei Yan
This work presents a novel heterogeneous catalytic system for the preparation of para -nitrotoluene ( p -NT) with nitrogen dioxide (NO 2 ) as a nitrating agent in the presence of oxygen (O 2 ). By applying dealuminated Hβ zeolite treated with oxalic acid (Hβ-Ox) as a catalyst, p -NT can be obtained with high conversion (90.5%) and selectivity (72.6%). In addition, it can be recycled at least five times without a significant decrease in catalytic activity. This result demonstrates that the catalyst has high efficiency, good stability, and regenerability. Meanwhile, the characteristics of pristine Hβ and different dealuminated Hβ zeolites modified with organic and inorganic acids were systematic contrastive studied using X-ray diffraction (XRD), nitrogen (N 2 ) adsorption-desorption, Fourier-transform infrared (FT-IR), scanning electron microscope (SEM), temperature-programed desorption of ammonia (NH 3 -TPD), pyridine adsorption infrared (Py-FT-IR), and solid state 27 Al nuclear magnetic resonance ( 27 Al MAS-NMR). Finally, the higher conversion and para -selectivity over Hβ-Ox also give a reasonable explanation in this paper.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2022
·
IF 5.436
Yingwu Zhou,Yujie Ban,Weishen Yang
Reversible phase transformations (RPTs) of metal–organic frameworks not only create material diversity but also promise a self-restoration of crystals in a controllable manner. However, there are only limited examples because seeking for a convenient and effective trigger for RPTs, especially for RPTs with respect to spatiotemporal harmony in cleavage and reconstruction of metal–linker chemical bonds, is challenging. In this work, we found that zeolitic imidazolate framework (ZIF)-108 with Zn–N coordination bonds showing moderate strength was an ideal platform. We reported three crystal phases of ZIF-108, namely, sodalite (SOD), diamondoid (DIA), and large pore_sodalite (lp_SOD) topologies, and identified RPTs between phases: (1) when exposed to water or water vapor, the SOD structure could transform to a compact DIA version as a result of the decomposition of four-membered rings and synchronous reorganization of six-membered rings. Then, the DIA structure could also return back to SOD when soaked in dimethylformamide (DMF) or DMF vapor. (2) High-temperature treatment of SOD gives rise to lp_SOD, which then reverts to SOD by DMF. (3) lp_SOD could also be compressed into the DIA phase by water or water vapor and can then be restored via a two-step treatment, namely, soaking in DMF (DIA → SOD) right before a high-temperature therapy (SOD → lp_SOD). From the perspective of the separation utility, we found that the lp_SOD version of ZIF-108, relative to SOD-structured ZIF-108, can produce mixed matrix membranes having an interesting interfacial structure with the polymer chains, though both share the same chemical composition. We verified that the large pore of lp_SOD can allow being penetrated by polymer chains, which contributed to not only reinforcing the bi-phase interface but also sharpening the molecule sieve properties of fillers toward CO2 and CH4.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）