CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2024
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IF 3.7
Lifang Ge,Meizhen Gao,Xiaosheng Zhang,Jiang Wang,Qi Shi,Jinxiang Dong
The adsorption and separation of diols from dilute aqueous solution using hydrophobic materials is very challenging due to the strong diol–water hydrogen-bonding interactions. Herein, we screened hydrophobic zeolitic imidazolate frameworks (ZIFs) with chabazite (CHA) topology for separation of 2,3-butanediol (2,3-BDO) and 1,3-propanediol (1,3-PDO), which had junctional and hydrophobic traps matching the two end methyl groups of the 2,3-BDO molecule. Based on CHA-ZIFs with the same small-sized ligand 2-methylimidazole (mIm) and different large-sized ligand benzimidazole derivatives (RbIm), CHA-ZIFs with larger surface areas were obtained by the addition of excess small-sized ligand mIm in the synthesis process. We showed that all of the hydrophobic CHA-ZIFs preferentially adsorbed 2,3-BDO over 1,3-PDO by static batch adsorption and dynamic column adsorption experiments. But ZIF-301 and ZIF-300 with halogen groups exhibited better adsorptive separation performance for 2,3-BDO/1,3-PDO than ZIF-302 with methyl groups. For a typical ZIF-301, its adsorption capacity for 2,3-BDO was 116.4 mg·g –1 and selectivity for 2,3-BDO/1,3-PDO was 3.8 in dynamic column adsorption of the binary-component system (2,3-BDO/1,3-PDO: 50/50 g·L –1 ). Computational simulations revealed that 2,3-BDO preferentially adsorbed in a trap at the junction between the cha and d6r cages of CHA-ZIFs, meaning the strong host–guest interactions. Therefore, the hydrophobic CHA-ZIFs with a junctional trap were promising candidate materials for adsorbing 2,3-BDO, which also provided a new perspective for separating diols in dilute aqueous solutions.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
·
IF 8.1
Li Peng,Zhaofeng Duan,Shumin Cen,Xuehong Gu
High-silica CHA (SSZ-13) zeolites membranes, with pore size between the molecular size of CO 2 and N 2 or CH 4 , are promising for some industrial CO 2 separation process. Considering water is typically present in these industrial gas feed and the negative impact of moisture on the membranes’ gas permeation, it is highly desirable to increase the surface hydrophobicity of membranes to reduce the adsorption of water. In this paper, a W-doping strategy was proposed to increase the hydrophobicity of SSZ-13 membranes by eliminating the silanols on the surface, and the W-doped high-silica CHA (W-SSZ-13) zeolite membranes were prepared for the first time. Characterizations such as SEM, XRD, and XPS confirmed the successful incorporation of W into CHA membrane. The incorporation of W reduced the pore mouth size, and the W-SSZ-13 zeolite membranes showed improved CO 2 /N 2 and CO 2 /CH 4 separation performance. After W-doping, the maximum separation factors ( α max ) for the CO 2 /N 2 mixture with equimolar composition under dry conditions increased from 8.8 to 16.9, and for the equimolar CO 2 /CH 4 mixture, the value increased from 105.9 to 176. The W-SSZ-13 membranes also showed better separation performance under wet conditions. For both systems, the W-SSZ-13 membrane showed higher α max and less CO 2 permeance reductions, indicating a more resistance in wet conditions.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
CATALYSIS TODAY
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2018
·
IF 4.667
Chaoqun Bian,Fang Chen,Ling Zhang,Weiping Zhang,Xiangju Meng,Stefan Maurer,Daniel Dai,Andrei-Nicolae Parvulescu,Ulrich Müller,Feng-Shou Xiao
High silica chabazite zeolite (CHA) is very important for selective catalytic reduction of NOx with ammonia (NH 3 -SCR), but its synthesis is time-consuming under conventional hydrothermal conditions (160 °C for 90–120 h). Herein, we report a novel strategy for highly efficient synthesis of CHA zeolite by means of fast crystallization at high temperatures in the absence of water solvent (240 °C for 1.5 h). X-ray diffraction, N 2 -adsorption isotherms, inductively coupled plasma, scanning electron microscopy, 29 Si and 27 Al MAS NMR, as well as thermogravimetry-differential thermal analysis suggest that the samples have high quality. This concept significantly enhances the space-time yields (STY) for CHA zeolite prepared from high-temperature synthesis in the absence of water solvent (almost two orders of magnitude higher than those of conventional hydrothermal synthesis). Moreover, compared with hydrothermal synthesis, the samples obtained from fast crystallization at higher temperatures (Si/Al = 12, 2.0% Cu loading) shows enhanced catalytic performance at 350–550 °C in NH 3 -SCR.
研究领域:
材料化学
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催化化学
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无机合成
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环境化学
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能源化学
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
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2024
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IF 7.4
Wenhan Wang,Wenqiang Li,Zijian Wang,Bo Liu,Bing Wang,Jingui Duan,Rongfei Zhou
Carbon dioxide capture is an effective method to mitigate climate change . Highly CO 2 -selective and highly moisture-resistant absorbent is essential for energy-efficient carbon capture by absorption. Herein, a highly CO 2 -selective and high-silica CHA zeolite in a pure lithium form (Li-SSZ-13) was synthesized using a direct synthesis method for the first time. The effects of gel n (SiO 2 )/ n (Al 2 O 3 ) ratio, gel n (SiO 2 )/ n (Li 2 O) ratio and synthesis time on the crystallinity , yield, micropore volume and CO 2 loading of the crystals were systematically investigated. The adsorption isotherms of CO 2 and N 2 were measured for directly synthesized Li-SSZ-13, conventional Na-SSZ-13 and ion-exchanged Li-Na-SSZ-13 zeolites. The dynamic breakthrough adsorption properties were measured for Li-SSZ-13 in comparison with Na-SSZ-13 and Li-Na-SSZ-13. The obtained Li-SSZ-13 exhibited a high CO 2 adsorption capacity of 4.48 mmol/g and a high CO 2 /N 2 IAST selectivity of 310 at 100 kPa and 273 K, which were 45.0 % and 441 % higher than Na-SSZ-13 zeolite, 24.8 % and 179 % higher than Li-Na-SSZ-13 zeolite, respectively. It suggests that directly synthesized Li-SSZ-13 zeolite has great potential for efficient CO 2 capture from flue gas .
研究领域:
材料科学
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环境科学
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DOI
高影响因子
SOLID STATE SCIENCES
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2021
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IF 3.059
Zhigang Yang,Dongliang Wang,Dong Ji,Guixian Li,Xinhong Zhao
The FeAPO-44 molecular sieve with CHA-type structure has been synthesized under solvent-free conditions. This is the first case that this material was successfully prepared by this novel solvent-free method. Its optimal synthesis conditions were refined. The results show that proper P 2 O 5 /Al 2 O 3 ratio, a lower SDA/Al 2 O 3 ratio (SDA: cyclohexylamine) and relatively mild crystallization temperature are more beneficial to the synthesis of pure CHA phase. The structural and compositional characteristics of the relatively pure FeAPO-44 zeolite were studied in depth by XRD , TG-DSC, CHN element analysis , EDS, SEM and N 2 physisorption. According to the CHN element analysis, EDS and TG-DSC measurements, the approximate chemical formula of the synthesized sample SDA/Al-1.4 was determined. The catalytic performances of selected samples were investigated in the methanol-to-olefins reaction. The present results imply that many other zeolite topologies may be conveniently prepared by this solvent-free route.
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
CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Yanpeng Chen,Rongshu Zhu,Guanyu Chen,Minghu Zhao,Min Ju,Rongming Cai,Jinqiang Gao,Mei Hong,Shihe Yang
Synthesis of small-pore chabazite (CHA) zeolites in the absence of organic structure-directing agents (OSDA) has been proven difficult. A judicious mixed cation approach recently reported could expand the design space of CHA formation. In a seemingly opposite direction, we herein report an anion tuning approach for controlling the zeolite polymorphism in an OSDA-free system that effectively promotes hierarchical CHA formation in a competitive growth with MER. Phenoxide media, utilizing mild in-situ nucleophilic etching in cooperation with zeolite framework growth, allow beneficial kinetic control to facilitate CHA nucleation. Operando analyses reveal the crucial role of stabilized dimeric aluminate species as a key intermediate for CHA phase selection. The phenol-mediated CHA zeolites exhibit almost perfect 9 molecules per unit cell CO 2 uptake capacity and no CH 4 adsorption. This work offers an anion tuning strategy for controlling zeolite polymorphism as a supplement to the current phase-selection toolbox that utilizes mixed inorganic cations.
研究领域:
材料科学
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化学工程
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环境科学
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产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
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2022
·Vol. 9
·期 6
·1300-1312
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IF 7.779
Nangui Lv,Chenhu Sun,Xueqin Wang,Chan Wang,Yuanyuan Yue,Xiaojun Bao
Synthesizing CHA-type zeolite via template-free interzeolite transformation has been considered as a green method, but the resultant zeolite exhibits low activity in the selective catalytic reduction of NOx by ammonia (NH3-SCR). Herein we report a highly active NH3-SCR catalyst (Cu-CHAUSY) derived from CHA-type zeolite (CHAUSY) that is synthesized via template-free interzeolite transformation from ultra-stable Y (USY). The ultra-high activity is attributed to the specific silicon and aluminum configurations in USY which are distinctly different from those in the conventionally used parent NaY, although they have similar SiO2/Al2O3 ratios. This characteristic endows CHAUSY with more single Al atoms in a six-membered ring, benefiting the self-reduction of [Cu(OH)]+ and the activation of O2 during the NH3-SCR reaction. Moreover, Cu-CHAUSY is demonstrated to outperform the two reference catalysts prepared from the aluminosilicate gel by conventional hydrothermal crystallization with the assistance of organic templates. Our work provides a new strategy for preparing highly active NH3-SCR catalysts.
研究领域:
化学工程
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催化科学
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DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2020
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IF 16.683
Juan Zhang,Yulong Shan,Ling Zhang,Jinpeng Du,Hong He,Shichao Han,Chi Lei,Sen Wang,Weibin Fan,Zhaochi Feng,Xiaolong Liu,Xiangju Meng,Feng-Shou Xiao
As a commerical catalyst of high silica CHA zeolite for NH 3 -SCR reaction, controllable Al sites in CHA framework for improving catalytic performance are rarely reported. In this work, two organic templates (TMAda + and DMCHA + ) were employed to prepare aluminosilicate CHA zeolite with similar Si/Al ratios, donated as CHA-T and CHA-D. Detailed characterizations demonstrate that two completely distinguishable crystallization pathways can be identified as the preferential formation of smaller D6R units for CHA-D with DMCHA + and larger 8MRs for CHA-T with TMAda + , resulting in spatially closer Al sites in CHA-D than CHA-T. As an interpretation, CHA-D with more paired Al atoms in 6MR generating more hydrothermally stable Cu 2+ -2Z sites contributes to higher activity than CHA-T at 400−550 °C. These results suggest that the crystallization pathways directed by rational choice of organic templates might be responsible for the controllable Al sites in the framework, which is important for designing efficient NH 3 -SCR catalysts.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Jingyan Zhang,Peng Ji,Li Ren,Yuhong Zhao,Shiqing Li,Hao Xu,Honggen Peng,Jin-Gang Jiang,Yejun Guan,Peng Wu
The small-pore CHA -type zeolites have received intensive attentions due to their outstanding performance in both of the methanol-to-olefin (MTO) process and ammonia selective catalytic reduction of nitrogen oxides (NH 3 -SCR of NO x ) reactions. However, the costly synthesis of CHA -type aluminosilicate is a great issue for the practical application. In this study, a novel and cheap organic structure-directing agent of N,N,N -trimethylisobutylammonium hydroxide was developed and used to synthesize CHA -type zeolites (name as ECNU-25) with boric acid as the supporting agent. The Si/Al ratio in the synthetic gel could be tailored in a wide range of 50 - ∞. [Al,B]-ECNU-25 zeolite thus synthesized served as an effective catalyst for the MTO reaction. After Cu 2+ -exchange, the Cu-[Al,B]-ECNU-25 was also highly active in the NH 3 -SCR of NO x .
研究领域:
化学工程
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环境科学
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催化材料
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产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2017
·Vol. 5
·期 19
·9076-9080
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IF 8.867
Xin Xiong,Dingzhong Yuan,Qinming Wu,Fang Chen,Xiangju Meng,Ruihua Lv,Daniel Dai,Stefan Maurer,Robert McGuire,Mathias Feyen,Ulrich Müller,Weiping Zhang,Toshiyuki Yokoi,Xinhe Bao,Hermann Gies,Bernd Marler,Dirk E. De Vos,Ute Kolb,Ahmad Moini,Feng-Shou Xiao
High silica CHA zeolite plays an important role in selective catalytic reduction of NOx with NH3 (NH3-SCR), but its synthesis is not highly efficient due to the use of a relatively high-cost structural directing agent (SDA) N,N,N-trimethyl-adamantammonium hydroxide (TMAdaOH) and relatively long crystallization time under hydrothermal conditions. Herein, we report an efficient and rapid synthesis of a high silica CHA zeolite possessing good crystallinity and uniform crystals (CHA-ST). The method includes interzeolite transformation of high silica FAU zeolite in the absence of water but the presence of zeolite seeds and a bromide form of the SDA. The absence of water in the synthesis significantly improves the zeolite yield by avoiding dissolution of aluminosilicate species in aqueous media, while the addition of zeolite seeds remarkably enhances the crystallization rate under solvent-free conditions. In addition, this route allows the use of a low-cost bromide form of the SDA. Catalytic tests in the NH3-SCR show that copper-exchanged CHA-ST (Cu-CHA-ST) exhibits comparable catalytic properties to those of Cu-SSZ-13 obtained from the conventional hydrothermal route.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
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2023
·Vol. 106
·期 2
·602-615
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IF 2.5
Zhang Lan,Ren Zexiao,Dong Xiang,Zhao Yan,Cen Qihong
Hierarchically structured CHA-type zeolite composite was fabricated from industrial wastes red mud and coal fly ash via a facile two-step method without the addition of templates. A macro-porous ceramic support was first sintered, then zeolite/ceramic composite was formed through alkaline hydrothermal reaction. The physico-chemical properties of the samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and surface area analyzer (BET). It was found that the as-prepared zeolite/ceramic composite featured micron sized CHA-type zeolite particles (14.1 wt%) on the macro holes and channels of its ceramic support, which developed a hierarchical structure. Compared to the ceramic support, its specific surface area was increased by 2400%. The successfully made zeolite/ceramic composite was tested as an adsorbent for Cs(I) adsorption in batch mode. The results showed that the adsorption of Cs(I) on ZCC can be well described by the pseudo-first-order model and Langmuir model with the maximum adsorption capacity of 34.5 mg/g (25 °C), which is nearly 8 times that of ceramic support. The thermodynamic studies revealed an endothermic and spontaneous process. TCLP results showed that all targeted toxic metals met the regulatory standard. Thus, the reported hierarchically structured zeolite synthesized from industrial solid wastes, exhibiting high adsorption capacity of Cs(I) ions and good environmental compatibility, has the potential to be applied in wastewater treatment. Graphical Abstract
Preparation of Ceramic support using fly ash and red mud, then hydrothermal reaction to obtain Zeolite/ceramic composite, followed by cesium ion adsorption experiments to obtain the conclusion that the adsorption performance of zeolite/ceramic composite is much better than that of the Ceramic support.
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
APPLIED CATALYSIS B-ENVIRONMENTAL
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2024
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IF 20.2
Chunlei Zhang,Guangyan Xu,Yanshuang Zhang,Chuang Chang,Miao Jiang,Luna Ruan,Min Xiao,Zidi Yan,Yunbo Yu,Hong He
Selective catalytic reduction of nitrogen oxides with methane (CH 4 -SCR) has emerged as a promising technology for mitigating exhaust emissions from natural gas vehicles, while its insufficient catalytic activity and durability are key barriers to application. In this study, novel Ce/In-CHA OXZEO catalysts were prepared, demonstrating exceptional catalytic performance and stability in the CH 4 -SCR reaction. Over these OXZEO catalysts, indium species predominantly existed in the form of InO + and In x O y within the CHA zeolite framework, while CeO 2 nanoparticles primarily resided as an external layer. During the CH 4 -SCR reaction, NO oxidation to form NO 2 and nitrate species was triggered by CeO 2 , which further enhanced the activation of CH 4 on InO + sites, thus boosting the low-temperature CH 4 -SCR process by facilitating the formation of the key intermediate CH 3 NO 2 . The synergy between InO + and CeO 2 underscores the exceptional performance and stability of the Ce/In-CHA with a low SiO 2 /Al 2 O 3 ratio in reducing NO x and CH 4 emissions.
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
危险品化学品经营许可证（带存储）