ENVIRONMENTAL TECHNOLOGY
·
2023
·
IF 2.8
Jiaying Zhu,Yanyang Wu,Bin Wu,Kui Chen,Lijun Ji
m-Cresol and p-cresol are widely used in medicine and pesticides as important chemical intermediates. They are generally produced as a mixture in industry and are difficult to separate due to the similarities in both chemical structures and physical properties. The adsorption behaviours of m-cresol and p-cresol on zeolites (NaZSM-5 and HZSM-5) with different Si/Al ratios have been compared by static experiments. Selectivity on NaZSM-5(Si/Al = 80) could be greater than 6.0. Adsorption kinetics and isotherms were investigated in detail. The kinetic data was correlated by PFO, PSO, and ID models, the NRMSE of which were 14.03%, 9.41%, and 21.11%, respectively. In the meanwhile, according to the NRMSE of Langmuir (6.01%), Freundlich (57.80%), D-R (1.1%), and Temkin (0.56%) isotherms, adsorption on NaZSM-5(Si/Al = 80) was mainly a monolayer and chemical adsorption process. It was endothermic for m-cresol and exothermic for p-cresol. The Gibbs free energy, entropy, and enthalpy were calculated accordingly. The adsorption of cresol isomers on NaZSM-5(Si/Al = 80) were both spontaneous, and it was exothermic (ΔH = −37.11kJ/mol) for p-cresol while endothermic (ΔH = 52.30kJ/mol) for m-cresol. Additionally, ΔS were respectively −0.05 and 0.20 kJ·mol−1·K−1for p-cresol and m-cresol, which were both close to zero. The adsorption was mainly driven by enthalpy. The result of breakthrough further demonstrated m-cresol and p-cresol could be separated effectively by NaZSM-5(Si/Al = 80). Additionally, the selectivity increased from 7.53 to 14.72 after four cycles regeneration with 9.95% and 53.96% decreases in the adsorption amounts for m-cresol and p-cresol, respectively. In conclusion, NaZSM-5(Si/Al = 80) could be a feasible adsorbent for the separation of m-cresol and p-cresol.
研究领域:
化学工程
·
材料科学
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产品关联
DOI
PubMed
高影响因子
FUEL
·
2021
·
IF 6.609
Mingquan Li,Aqsa Noreen,Yajie Fu,Cederick Cyril Amoo,Yujia Jiang,Xu Sun,Peng Lu,Ruiqin Yang,Chuang Xing,Shurong Wang
Directly synthesizing olefins from syngas using metal-zeolite composite catalysts has engrossed a lot of attention recently. Fe-based catalysts will be the most promising industrial candidates due to cost and availability constraints. In this work, we investigate the characteristics and Fischer-Tropsch activity of a novel Fe@Na-ZSM-5 composite for one-step conversion of syngas to higher olefins (C 5+ ). The in-situ crystallization mechanism induced Na in the ZSM-5 as a Fe-based promoter which realized 52.5 % selectivity for gasoline of which ∼ 70% were olefins. Additionally, the promotion by the Na ions enhanced the formation of Fe 5 C 2 phases which in turn favored C–C coupling, high gasoline and olefins selectivity. Na type zeolite (Na-Zeolite) offers a novel Na electron promoter, which participate immensely in the development of heterogenous catalyst and functional materials.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2019
·
IF 4.888
Yiwen Jiang,Ling Zhang,Yiquan Xie,Shichao Han,Qiuyan Zhu,Xiangju Meng,Feng-Shou Xiao
A series of zeolite-supported Pt nanoparticles (Pt/NaZSM-5) have been prepared by adjusting Si/Al ratio of NaZSM-5 zeolite from 60 to pure silica. Catalytic tests in propene oxidation as an important model reaction for removal of hydrocarbons emitted from automobiles during cold-start, show that the catalytic activities significantly increase with Si/Al ratios of NaZSM-5 zeolite in these Pt/NaZSM-5 catalysts. As a typical example, Silicalite-1 supported Pt nanoparticles exhibits the highest activity, giving the 50% conversion temperature (T 50 ) and 90% conversion temperature (T 90 ) at 112 °C and 118 °C, respectively. Characterizations of these catalysts with multiple techniques show that the enhanced catalytic activities are strongly related to the zeolite Si/Al ratios of the catalysts, where an increase of zeolite Si/Al ratio is favorable for the adsorption of propene, promoting the propene oxidation. This feature might offer a good opportunity to design and prepare highly efficient heterogeneous catalysts for removal of light olefins in the future.
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
Nanomaterials
·
2022
·Vol. 12
·期 11
·1803
·
IF 5.719
Tinglong Yang,Mengqin Yao,Jun Ma,Peng Chen,Tianxiang Zhao,Chunliang Yang,Fei Liu,Jianxin Cao
In this paper, the molecular sieve NaZSM-5 was modified with zirconium dioxide (ZrO2) by a hydrothermal coating process and other methods. By comparing the effects of the crystal phase structure of ZrO2and the compositing method on the physicochemical properties and catalytic performance of the obtained composites, the structure–performance relationship of these composite catalysts was revealed. The results indicate that in the hydrothermal system used for the preparation of NaZSM-5, Zr4+is more likely to dissolve from m-ZrO2than from t-ZrO2, which can subsequently enter the molecular sieve, causing a greater degree of desiliconization of the framework. The larger specific surface area (360 m2/g) and pore volume (0.52 cm3/g) of the m-ZrO2/NaZSM-5 composite catalyst increase the exposure of its abundant acidic (0.078 mmol/g) and basic (0.081 mmol/g) active centers compared with other composites. Therefore, this catalyst exhibits a shorter induction period and better catalytic performance. Furthermore, compared with the impregnation method and mechanochemical method, the hydrothermal coating method produces a greater variety of acid–base active centers in the composite catalyst due to the hydrothermal modifying effect.Keywords:ZrO2crystalline phase;NaZSM-5 modification;hydrothermal coating strategy;Si/Al ratio;methanol thiolation
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）