RSC Advances
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2017
·Vol. 7
·期 54
·33714-33725
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IF 3.108
Jianhua Li,Haiyan Liu,Tingting An,Yuanyuan Yue,Xiaojun Bao
This article describes a novel method to dealuminate and realuminate H-beta zeolites as catalysts for removing organic acids from bio-oils via their esterification reactions with alcohols. Modified H-beta zeolites were prepared by leaching with solutions of oxalic acid, DL-malic acid, and DL-tartaric acid that have different numbers of hydroxyl groups. The results showed that, while all three organic acids can dealuminate the parent H-beta zeolite, with Al(VI)a atoms and Al(IV)c ones being preferentially removed, they show quite different realumination abilities, with tartaric acid with two hydroxyl groups having the highest realumination ability. The concomitance of dealumination and realumination and their dependence on the hydroxyl group numbers of the organic acids provide the possibility of finely tuning the Al and acidity distributions of the resulting zeolites. Among the three acid treated H-beta zeolites, the one obtained from malic acid leaching exhibited the best performance in catalyzing the esterification reaction between acetic acid and sec-butyl alcohol, attributed to its suitable quantity and density of medium and strong Brönsted acid sites and enhanced aluminum gradient. The catalytic results obtained in a fixed-bed microreactor revealed that the malic acid leached H-beta exhibited dramatically enhanced catalytic performance compared to the commercial ion-exchange resin Amberlyst® 15, demonstrating great potential for industrial application.
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2017
·
IF 2.843
Peng Liu,Ni Yuan,Wei Xiong,Hanyu Wu,Duoqiang Pan,Wangsuo Wu
β-Zeolite was synthesized and modified with ethylenediamine (EDA). The synthesized materials were characterized and used for the removal of nickel(II) from aqueous solutions. The influences of the pH, contact time, and temperature on nickel(II) adsorption onto synthesized β-zeolite and β-zeolite modified with ethylenediamine (β-zeolite–EDA) were studied by a batch technique, and X-ray photoelectron spectroscopy was employed to analyze the experimental data and identify the formation of coordination bonds between the adsorbents and nickel(II). The dynamic process showed that the adsorption of nickel(II) onto β-zeolite and β-zeolite–EDA matched the pseudo-second-order kinetics model, and the adsorption of nickel(II) was significantly dependent on the pH values. Through simulation of the adsorption isotherms by the Langmuir, Freundlich, and Dubinin–Radushkevich models, it could be seen that the adsorption patterns of nickel(II) onto β-zeolite and β-zeolite–EDA were mainly controlled by surface complexation and the adsorption processes were endothermic and spontaneous. The modification of β-zeolite–EDA improved the adsorption capacity of nickel(II) significantly; this shows a novel material for the removal of nickel(II) from the water environment for industrialized application.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
ENERGY & FUELS
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2025
·
IF 5.3
Jing Li,Suxia Ma,Nuo Xu
Fly ash, a solid waste rich in silicon (Si) and aluminum (Al), offers significant potential for valorization through the high-value synthesis of zeolites, exemplifying the waste-to-wealth approach. We determined the optimal synthesis conditions for FA-β zeolite using the alkali fusion hydrothermal synthesis method, with fly ash as the primary raw material. The conditions included a NaOH/FA ratio of 1.2, a SiO2/Al2O3 ratio of 30, an H2O/Al2O3 ratio of 1200, a TEAOH/Al2O3 ratio of 14, a β-seed addition of 7.5%, and hydrothermal conditions of 140 °C for 72 h. XRD and FTIR analyses confirmed that the diffraction peaks of the synthesized fly ash-based zeolite align well with the standard pattern of commercial β zeolite. Removal experiments indicated that the efficiency of nitrogen oxides removal hinges on the adequate oxidation of NO. Under optimized conditions, the FA-β zeolite demonstrated a removal efficiency of 83%. ESR analysis revealed that the removal mechanism involves the oxidative elimination of NO, catalyzed by FA-β zeolite through the decomposition of H2O2 to OH radicals. This novel synthesis method, which utilizes fly ash as the raw material to prepare β zeolite, offers advantages in terms of cost-effectiveness and environmental protection. It holds significant potential for applications in environmental conservation.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
Molecular Catalysis
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2018
·
IF 0
Yueqing Wang,Xiaohai Yang,Hongyan Zheng,Xianqing Li,Yulei Zhu,Yongwang Li
The mechanism for the formation of furfural by dehydration of d -fructose via selective carbon-carbon (C C) bond cleavage was investigated over beta zeolite (Hβ). Several different pore size zeolites were employed to determine the shape selectivity of fructose isomers. Zeolitic pore sizes that smaller than the kinetic diameter of cyclic fructose also produced yield furfural (∼22.5%), while the high yield (66.0%) of hydroxymethylfurfural (HMF) can be achieved over large pore zeolite (USY zeolite), which could accommodate the cyclic fructose. These results indicated that the furfural formation likely began with acyclic fructose. In situ 13 C NMR and GC MS studies, using labeled 13 C-1-fructose as substrate, suggested that the conversion of fructose to furfural involved with splitting of the C5-C6 bond. Furthermore, the C1 compound from the cleavage of C C bond was identified as formaldehyde, inferring that the selective scission of C C bond was ascribe to the retro-aldol reaction. Interestingly, in situ NMR studies implied that the acyclic fructose mainly derived from pyranose forms. In addition, compared with glucose, fructose directly converted to furfural at the higher yield and reaction rate.
研究领域:
催化化学
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有机化学
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DOI
MICROPOROUS AND MESOPOROUS MATERIALS
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2021
·
IF 5.455
Zijun Yang,Qiang Yu,Yonghua Guo,Xiaoxia Wu,Hua Wang,Jinyu Han,Qingfeng Ge,Xinli Zhu
Heteroatom metal-zeolite, with heteroatom metal (oxide) dispersed in the zeolite framework, enables the reactions typically catalyzed by bulk metal oxide counterpart but with maximized the atomic utilization. However, the distribution of heteroatoms in the framework is strongly influenced by the preparation method. In this work, Ti-Beta zeolites were postsynthesized using the recrystallization (Ti-Beta-Re) and solid-state ion-exchange (Ti-Beta-SSIE) methods. Characterizations showed that more Ti species were incorporated in the tetrahedral framework site of Ti-Beta-Re to form Lewis acid sites than in that of Ti-Beta-SSIE. In addition, intra-crystallite mesopores were developed in Ti-Beta-Re due to partial dissolution of BEA framework during alkaline etching and subsequent recrystallization of the etched framework. These zeolites were then tested for ketonization of biomass derived propionic acid at 350 °C and atmospheric pressure. The turnover frequency of ketonization was found to be 25% higher on Ti-Beta-Re (0.25 min −1 ) than on Ti-Beta-SSIE (0.20 min −1 ), whereas the apparent activation energy of 80 kJ/mol on Ti-Beta-Re is lower than 95 kJ/mol on Ti-Beta-SSIE. Moreover, the selectivity of 3-pentanone kept > 95% on Ti-Beta-Re while it dropped to ∼63% on Ti-Beta-SSIE with increase of reaction time at a space time of 2 h. This work demonstrated that the tetrahedrally coordinated Ti species are the active sites and the presence of intra-crystallite mesopores facilitates selective ketonization of carboxylic acids.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2021
·
IF 3.764
Zhongwen Dong,Xinyi Wang,Weifeng Chu,Chuanyu Yang,Yanan Wang,Lin Mei,Dongpu Zhao,Wenjie Xin,Shenglin Liu,Hongxia Wang,Yongchen Shang,Longya Xu
A fast synthetic methodology of β-zeolite with the assistance of γ-butyrolactone (GBL) has been developed in this paper, and the synthetic parameters are systematically investigated to obtain β-zeolite efficiently. Compared to the conventional synthetic system with a crystallization time of 120 h, GBL promotes the crystallization of β-zeolite in a much shorter time of 24 h. An accelerated nucleation mechanism of β-zeolite assisted by GBL is unraveled by X-ray diffraction, scanning electron microscopy, thermogravimetry–differential thermal analysis, Fourier transform infrared spectroscopy, and NMR techniques. The results demonstrate that GBL can adjust the pH value of the initial gels and enhance the combination of TEA+ with aluminosilicate species; in the meantime, the Hoffmann degradation of TEAOH is suppressed. In addition, the β-catalyst obtained with the assistance of GBL exhibits both a higher selectivity of tert-butylbenzene and excellent catalytic stability in the alkylation of benzene with isobutylene compared with the commercial β-catalyst with a similar SiO2/Al2O3 molar ratio.
研究领域:
化学工程
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催化材料
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DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Zhongdi Liu,Rui Zhang,Huai Liu,Junhua Zhang,Yong Sun,Naya Li,Lincai Peng
Developing efficient and stable solid functional materials for the catalytic upgrading of biomass-based platform furanic molecules is of great significance to produce value-added chemicals and biofuels. We herein report β-zeolite (β)/biobased carbon hybrids supported Zr species towards the cascade conversion of furfural into γ-valerolactone (GVL) with high activity and favorable stability. The role and importance of carbon modifier were highlighted. The cellulose (CEL) modified Zr/β-CEL catalyst was found to be uniquely effective, leading to an increase of GVL yield from 49.3% to 81.1%. Catalyst characterizations revealed that the structural integrity of β was largely preserved using CEL as the carbon modifier, accompanied by the increased mesopore volume and pore size for better accessibility of active sites and diffusion of reactants. Simultaneously, the presence of CEL offered an appropriate ratio of Lewis and Brønsted acid sites due to the well incorporation and dispersion of Zr species, which ensured the successive transfer hydrogenation and ring-opening reactions. Kinetic studies demonstrated the positive effect of CEL modification on reducing the apparent activation energy and thereby facilitating the GVL formation. More importantly, Zr/β-CEL with enhanced structural stability also exhibited markedly higher recyclability compared with the pristine Zr/β. The understanding on the roles of carbon modifier can be employed to optimize the physicochemical properties of zeolite-based catalysts for roundly improving the catalytic reactivity of biomass-related compounds.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
JOURNAL OF POROUS MATERIALS
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2018
·Vol. 26
·期 4
·1017-1025
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IF 1.858
Liu Zhen,Zhao Liang,Zhang Tingting,Wang Yu,Xu Yanyan,Komarneni Sridhar,Wang Yi,Liu Xinmei,Yan Zifeng
The traditional silicon sources for beta zeolite synthesis are solid silica gel, carbon-white or tetraethyl orthosilicate (TEOS), which makes the material cost even higher. Herein, beta zeolite synthesis by hydrothermal method with industrial silica sol as silicon source was investigated. The effects of synthesis conditions on product property were investigated in detail, including template content, crystallization temperature, crystallization time and alkalinity of hydrothermal system. The products properties, such as crystallinity, pore structure, morphology and acid properties were thoroughly characterized by XRD, N 2 adsorption–desorption isotherm, SEM, TEM, Py-FTIR and NH 3 -TPD. The optimum condition for synthesis of beta zeolite using industrial silica sol as silicon source was finally determined. Compared with commercial beta zeolite, the as-synthesized beta zeolite had higher relative crystallinity, higher total and microporous specific surface area with higher total concentration and B/L ratio of acid sites.
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
Energy Technology
·
2016
·Vol. 5
·期 5
·747-755
·
IF 2.557
Tingwei Zhang,Wei Fan,Wenzhi Li,Zhiping Xu,Haosheng Xin,Mingxue Su,Yijuan Lu,Longlong Ma
Sn-β zeolite and PTSA–POM, made from the copolymerization of p -toluenesulfonic acid (PTSA) and paraformaldehyde (POM), were used for the production of 5-(hydroxymethyl)furfural (HMF) from glucose in an environmentally friendly solvent system including γ-valerolactone (GVL) and H 2 O. The effects of reaction temperature, reaction time, solvent, and catalyst-to-reactant ratio on the production of HMF were investigated. The combination of the Brønsted acid and Lewis acid catalysts largely improved the catalytic system and resulted in the production of HMF in 60.1 % yield at 140 °C in 30 min. The presence of water in the solvent had a positive influence on the production of HMF from glucose. The combination of the two catalysts also improved the catalytic performance for the production of HMF from cellulose and corn stalk.
研究领域:
化学工程
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可再生资源转化
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催化科学
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DOI
高影响因子
CATALYSIS COMMUNICATIONS
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2018
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IF 3.463
Chengwu Dong,Changlong Yin,Tongtong Wu,Zhuyan Wu,Dong Liu,Chenguang Liu
An unsupported Ni Mo catalyst was modified by β-zeolite nanoclusters synthesized by the hydrothermal method. The effect of the nanoclusters on the acidity of unsupported catalyst was studied. Results showed that the Lewis acid and the total acid amount of the unsupported catalyst were improved. Indicating that the β-zeolite nanoclusters was successfully introduced into the unsupported catalyst. And the catalytic activity results showed that the introduction of β-zeolite nanoclusters not only led to the higher desulphurization and isomerization activity, but also improved the ratio of direct desulfurization paths (DDS), which is in favor of reducing hydrogen consumption.
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
FUEL
·
2025
·
IF 7.5
Xiaowei Wu,Yuqin Li,Zhengquan Yang,Mingyu Peng,Tian Gui,Xiangshu Chen,Hidetoshi Kita
A beta zeolite membrane reactor was first applied to improve conversion on the esterification of oleic acid and n-butanol at low temperature by rapidly removing the by-product water. In the pervaporation (PV)-esterification at low temperature of 353 K, the final conversion of oleic acid was significantly improved to 99.2 % in a short reaction time of 4 h. Even at an incredibly low esterification temperature of 333 K, the conversion of oleic acid reached 95.7 % in 4 h. Besides, the beta zeolite membrane reactor exhibited good hydrothermal and acid stabilities with a high oleic acid conversion (maintained above 99 %) after 5 reaction cycles. Through XRD and SEM characterization, it was found that the membrane kept complete crystal structure. Process intensification through a beta zeolite membrane reactor aided by PV was successfully used to enhance the esterification at low temperature in a short time, which was a promising coupling technology.
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
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2021
·
IF 5.455
Guochao Yang,Lingtao Wang,Haoxi Jiang
The conversion of ethanol to butadiene catalyzed by modified β zeolites has attracted wide attention. The construction of intracrystalline mesoporosity in β zeolite is a challenging way to improve the catalytic activity. In this work, a surfactant-template strategy was used to construct intracrystalline mesoporosity successfully in the alkali treatment of β zeolite using long-chain quaternary ammonium salt with different alkyl chain length (C10~C16) as the template. The intracrystalline pore size can be adjusted by varying the surfactant alkyl chain length (C10~C16) (1.9–3.4 nm). To get more information about this process, CTAB was chosen as the template in further investigations. The mesoporosity can be generated within 1 h. The BET surface area can reach up to 600 m 2 /g while the pore volume can reach up to 0.568 cm 3 /g, which are 1.23 and 1.5 times that of the parent zeolite, respectively. The template action of CTA + is essential for forming mesoporosity, and CTA + interacts with the zeolite during the alkali treatment process, protects the zeolite framework from being etched, and does not form a separated mesoporous phase. To demonstrate the effect of intracrystalline mesoporosity on the catalytic performance, Zr-β zeolite was prepared and used as the catalyst for ethanol-acetaldehyde conversion. The hierarchical Zr-β zeolite was prepared using a dealumination-metallization strategy, and both the zeolite crystallinity and the mesoporosity were preserved in this process. The total conversion increased by 10%, while the BD selectivity was well maintained. The catalytic performance showed that the introduction of mesoporosity effectively mitigated decreasing conversion while preserving BD selectivity.
研究领域:
催化材料
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化学工程
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产品关联
DOI
高影响因子
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