Reaction Kinetics Mechanisms and Catalysis
·
2015
·Vol. 117
·期 1
·239-251
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IF 1.17
Geng Gaoli,Wei Ruiping,Liang Ting,Zhou Minghao,Xiao Guomin
A series of Cu–Ca–Al hydrotalcite derived catalysts were prepared by the co-precipitation method. Their catalytic activities were evaluated in the hydrogenolysis of glycerol. The catalysts were characterized by XRD, SEM, TEM, ICP, NH 3 -TPD, CO 2 -TPD and H 2 -TPR. It was observed that the incorporation of calcium and aluminum in the Cu–Ca–Al catalyst improved the conversion of glycerol and promoted the generation of 1,3-PDO. This is due to the appropriate acidity and basicity of the catalyst, which is confirmed by NH 3 -TPD and CO 2 -TPD. The conversion of glycerol over the catalyst with a Cu–Ca–Al mole ratio of 1:3:5 was up to 73.2 % with 42.6 % selectivity to 1,2-PDO and 9.1 % selectivity to 1,3-PDO. Effects of the reaction time, reaction temperature and initial hydrogen pressure on the conversion and selectivity were systematically investigated.
研究领域:
化学工程
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催化材料科学
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DOI
高影响因子
GREEN CHEMISTRY
·
2017
·Vol. 19
·期 21
·5103-5113
·
IF 9.125
Ying Duan,Min Zheng,Dongmi Li,Dongsheng Deng,Lu-Fang Ma,Yanliang Yang
The catalytic conversion of HMF to 2-hydroxy-3-methyl-2-cyclopenten-1-one (MCP), which is a valuable edible essence that has traditionally been obtained from adipic acid, was achieved with an isolated yield of 58%. This procedure comprised two steps: the hydrogenation of 5-hydroxymethylfurfural (HMF) to 1-hydroxy-2,5-hexanedione (HHD) in water on Pd/Nb2O5 catalysts and then the isomerization of HHD to MCP in the presence of a base. The Nb2O5 supports, which were acidic, were characterized by FTIR, XRD and NH3-TPD. The supported Pd/Nb2O5 catalysts, in which Pd was highly dispersed, were synthesized employing cyclohexene as a reductant and were characterized by XRD, TEM, ICP-AES, XPS, EDX and CO pulse chemisorption. The high conversion of HMF was attributed to the high dispersion of Pd, and the acidity of the supports led to high selectivity for HHD. The conversion of HHD to MCP was an intramolecular aldol condensation reaction, and the protonic solvent favored this reaction. Ca–Al was proved to be an effective solid base for the conversion of HHD to MCP in water.
研究领域:
化学工程
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催化化学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2017
·
IF 6.065
Haijun Chen,Zhe Chen,Guixia Zhao,Zhibin Zhang,Chao Xu,Yunhai Liu,Jing Chen,Li Zhuang,Tasawar Haya,Xiangke Wang
Ca/Al layered double hydroxide decorated carbon nanotube (Ca/Al-LDH@CNTs) composites were fabricated by co-precipitation method and hydrothermal aged treatment. The prepared Ca/Al-LDH@CNTs was characterized by SEM, TEM, EDS, XRD, FT-IR, UV–vis and XPS techniques, and applied to remove U(VI) from aqueous solutions under various environmental conditions (i.e., pH, ionic strength, temperature and contact time). The results indicated that the adsorption of U(VI) on Ca/Al-LDH@CNTs was four times higher than that of U(VI) on bare CNTs. The kinetic investigations reflected the chemisorption of U(VI) on Ca/Al-LDH@CNTs through oxygen-containing functional groups. The adsorption isotherms demonstrated that the adsorption of U(VI) was well fitted by Langmuir model and the maximum adsorption capacity of U(VI) on Ca/Al-LDH@CNTs was calculated to be 382.9 mg g −1 at 289.15 K. The thermodynamic parameters calculated from temperature-dependent isotherms suggested that U(VI) adsorption on Ca/Al-LDH@CNTs were endothermic and spontaneous process. Furthermore, Ca/Al-LDH@CNTs could remove ∼91% of 241 Am(III) at pH = 8.0, which confirmed Ca/Al-LDH@CNTs as a promising material for multiply low level radionuclides’ pollution remediation.
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
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2024
·
IF 7.1
Linjia Li,Yiran Zhang,Jiaqi Feng,Shu Zhao,Ke Li,Zhen Huang,He Lin
Integrated carbon capture and utilization (ICCU), based on dual-function materials (DFMs), is an emerging technology for carbon dioxide (CO2) emission control. DFMs composed of Ni–Ca–Al systems are favored owing to their affordability. However, their performance needs to be further improved. In this study, Ni/AlCaOx DFMs are prepared by one pot-impregnation method, reaching an adsorbing capacity of 1796 μmol CO2/gDFM and a production of 1790 μmol CH4/gDFM after ten cycles at 450 °C. The Ni–Ca–Al synergistic effect was investigated to understand the good performance of DFMs: during H2 pretreatment, Ca can weaken the strong interaction of Al–Ni and promote the reduction of NiO by facilitating Ni to gain electrons from H2, where Al may act as an intermediate carrier for electron transfer. In the carbonation process, Al modulates the synergistic interaction between Ca and Ni by regulating the spacing and distribution of catalytic and adsorption sites to improve the Ni/AlCaOx cycling performance. Besides, oxygen vacancies can also enhance the DFMs’ carbon capture performance. During the methanation process, Ni reduces the decomposition temperature of the carbonate formed at strongly basic sites, favoring the methanation reaction.
研究领域:
化学工程
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环境科学
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材料科学
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DOI
高影响因子
APPLIED ENERGY
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2022
·
IF 11.446
Xianyao Yan,Yingjie Li,Chaoying Sun,Chunxiao Zhang,Liguo Yang,Xiaoxu Fan,Leizhe Chu
The sorption-enhanced steam gasification of biomass (SESGB) using CaO-based materials is considered as a promising method for H 2 production. Ca-Al-Ce material has been reported as a good bi-functional material in SESGB process. Red mud is a solid waste in aluminium industry with large yield, which is rich in Fe 2 O 3 . In this work, a red mud-doped Ca-Al-Ce bi-functional material was prepared by wet-mechanical mixing method for H 2 production from SESGB. The CO 2 capture, H 2 production, and tar reduction performances during SESGB process using the red mud-doped Ca-Al-Ce bi-functional material were studied. The results show that the optimum addition amount of red mud in the bi-functional material is 5 wt%. After 20 SESGB cycles, the H 2 concentration using the red mud-doped Ca-Al-Ce material achieves 65.1 vol%, which is 82.4% higher than that using Ca-Al-Ce material. Besides, with the addition of red mud in the bi-functional material, the tar, residue char yields and CO 2 concentration decrease by 25.2%, 8.6% and 52.2%, respectively. Fe 2 O 3 in the red mud reacts with CaO to form Ca 2 Fe 2 O 5 in the 1st cycle, and Ca 2 Fe 2 O 5 is stable during 20 cycles, which is beneficial for the generation of oxygen vacancy. The oxidation states of Fe species in the material increase with the number of SESGB cycles, thus the catalytic effects on water gas shift reaction and tar reduction are promoted. The red mud addition is the key factor that results in high H 2 production, CO 2 capture and tar reduction performances, so the red mud-doped Ca-Al-Ce material appears promising for SESGB.
研究领域:
能源科学
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材料科学
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产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2025
·
IF 5.4
Yang Zhang,Hanjun Wu,Zhenyue Zhang,Wenda Guo,Junxia Yu,Rongying Zeng,Ruan Chi,Zhiquan Pan
In this work, Ca-Al LDHs were modified via co-precipitation method utilizing two distinct chemical forms of adipic acid (adipate salt and adipic acid) as intercalation agents, with the resulting materials denoted as At-LDHs (adipate-intercalated LDHs) and Aa-LDHs (adipic acid-intercalated LDHs). The results indicated that At-LDHs and Aa-LDHs all exhibit a sheet-like porous structure stacked with each other. Due to the different synthesis conditions, the sheet structure of Aa-LDHs is smaller than that of At-LDHs. The kinetic and isotherm simulation results indicated that the capture capacity of At-LDHs for Mn 2 + was up to 227.53 mg·g −1 when the pH value was 7, while that of Aa-LDHs for naphthol green B reached to 132.73 mg·g −1 at a pH value of 9. The kinetic and thermodynamic simulation results indicated that the capture of Mn 2+ by At-LDHs conformed to the pseudo-first-order kinetic model and the Langmuir isotherm model, and the capture of naphthol green B by Aa-LDHs conformed to the Elovich kinetic model and the Temkin isotherm model. In addition, the capture process of both was a spontaneous exothermic reaction. Benefiting from the excellent adsorption properties of At-LDHs composites (Ion exchange, electrostatic attraction, adsorption precipitation, functional group chelation), the adsorption effect on Mn 2+ was better. Aa-LDHs have good adsorption effect on naphthol green B in solution through electrostatic attraction, dipole-dipole hydrogen bond, Yoshida hydrogen bond and n-π interaction. At-LDHs and Aa-LDHs have great potential to be employed as the materials for the removal of organic and inorganic composite pollutants from wastewater.
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
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Qi Li,Jianliang Xie,Jin Hu,Xin Wang,Chengyong Yu,Shaoliang Jiang,Peng Liu,Chengli Sun,En Li,Longjiang Deng
The dielectric layer plays a key role in regulating electromagnetic wave broadband scattering based on meta-surface technology. Herein, the physical properties of composite powder, prepared by spray drying of CaO-B 2 O 3 -SiO 2 (CBS) glass-ceramic powder and Al 2 O 3 in different mass ratios, are systematically investigated. Meanwhile, a high enthalpy atmospheric plasma spraying equipment is utilized to prepare CBS/Al 2 O 3 composite coatings , and the morphology, physical properties and dielectric properties of the composite coating are analyzed. The XRD and DSC data of the composite coating reveal that the crystallization behavior of β-CaSiO 3 and CaB 2 O 4 gradually disappear with the increase of Al 2 O 3 content. Hence, only CaAl 2 Si 2 O 8 phase is observed during heat treatment. The experimental results confirm that the dielectric properties of CBS/Al 2 O 3 composite coating conform to the rule of mixture for composite materials. Also, the dielectric properties are affected by porosity and crystallization rate.
研究领域:
材料科学
·
电磁工程
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涂层与薄膜
·
复合材料
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产品关联
DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 104
·60025-60033
·
IF 3.708
Juan Chen,Lihua Jia,Xiangfeng Guo,Lijun Xiang,Shengfeng Lou
A series of KF-modified Ca–Al hydrotalcite (xKF/HTL-M) solid base catalysts was prepared in methanol, and characterized by thermogravimetry analysis (TG-DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and carbon dioxide temperature-programmed desorption (CO2-TPD). The catalytic activity was investigated in the transesterification of ethylene glycol monomethyl ether (EGME) with methyl laurate (ML) to produce a novel biodiesel of ethylene glycol monomethyl ether monolaurate (EGMEML). The effect of the mass content of KF and the main reaction parameters such as EGME to ML molar ratio, amount of catalyst, reaction time and temperature on the yield of EGMEML were examined. The results indicate that a new phase of KCaF3 formed in xKF/HTL-M, and acted as the main active sites for the transesterification. In addition, xKF/HTL-M has excellent catalytic performance in the production of EGMEML. The highest yield of 97.7% was obtained over 24.7KF/HTL-M at EGME/ML molar ratio of 3.0, catalyst amount of 5 wt%, and reaction time of 4 h at 120 °C. Moreover, the catalyst displays a good stability and reutilization. A satisfactory yield of 90% was obtained after use for five consecutive cycles without significant deactivation. Finally, the activation energy (Ea) of the reaction of EGME with ML over 24.7KF/HTL-M was obtained as 27.11 kJ mol−1.
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
SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Yong Zhang,Siqi Huang,Bingyu Mei,Lingyi Jia,Jun Liao,Wenkun Zhu
A novel dopamine-supported Mg( Ca )Al layered double hydroxide composite was synthesized by co-precipitation method. The existence of Ca 2+ and dopamine could promote the capture of uranium on the layered double hydroxides. In batch experiments, the composite exhibited good uranium removal performance, including high adsorption capacity (687.3 mg/g), strong anti-interference and good reusability (the removal percentage was still higher than 90 % after five cycles). At low initial uranium concentration, the uranium removal percentage on the composite exceeded 99.7 % and the residual concentration of uranium in the solution was <0.03 mg/L, reaching the limited standard of the World Health Organization. The studies of adsorption kinetics and isotherm indicated that the uranium adsorption behavior on the composite conformed to the pseudo-second-order kinetic and Langmuir isotherm models, suggesting that the process was a monolayer adsorption dominated by chemical adsorption. Furthermore, the high-efficiency uranium adsorption on the Mg( Ca )Al layered double hydroxide was mainly attributed to the strong complexation between the active sites (-OH and -NH 2 ) and uranium, the precipitation of interlayer intercalation ions (CO 3 2− and OH − ) to uranium and the ion exchange of Ca 2+ to uranium. Due to these advantages, the dopamine-supported Mg( Ca )Al layered double hydroxide composite is expected to be used as fine adsorbent to remove uranium from wastewater.
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
PubMed
高影响因子
Arabian Journal of Chemistry
·
2023
·
IF 6
Fulong Cheng,Yinian Wang,Yuting Fan,Dan Huang,Jie Pan,Wei Li
Biochar-based adsorbents for phosphate removal from wastewater has gained increasing attention and achieved significant progress. However, there is still much room for the enhancement on adsorption performance in terms of removal rate, adsorption capacity and pH application range. Herein, novel Ca-Al-La modified biochar adsorbents in this study were synthesized for enhancing phosphate adsorption in wastewater. The synthesis parameters of adsorbents were optimized by using the response surface methodology (RSM). The Ca-Al-La modified biochar adsorbent synthesized under the optimal conditions (CAL-MBC) exhibited superior adsorption capability towards phosphate. Specifically, CAL-MBC achieved a rapid removal rate to reach the adsorption equilibrium within 1 h, a maximum phosphate adsorption capacity of 152.9 mg/g, and excellent pH stability within a broad pH range of 3.0–11.0. The adsorption mechanisms involving electrostatic interaction, precipitation and inner-sphere complexation via ligand exchange were responsible for the excellent adsorption performance of phosphate on CAL-MBC. This study verifies CAL-MBC as a promising metal modified biochar adsorbent to enhance phosphate removal from wastewater.
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产品关联
DOI
高影响因子
ENVIRONMENTAL RESEARCH
·
2025
·
IF 7.7
Yupeng Wang,Xiangyuan Yu,Shulong Wen,Yihu Sun,Huibin Wei
The effective and economical removal of heavy metal-organic complexes remain an urgent challenge in the field of industrial wastewater treatment. In this study, Ca-doped ferrihydrite composites and Ca/Al co-doped ferrihydrite composites were synthesized via a simple one-step co-precipitation method and applied for the oxidative removal of EDTA-Cu in a hypochlorite system. The incorporation of Al significantly enhanced the material's stability. The Fe-Ca-Al composite exhibited a catalytic degradation efficiency of 97 % after 4 reaction cycles, representing a 32 % improvement compared to the Ca-doped ferrihydrite (Fe-Ca). Mechanistic studies revealed that the Fe-Ca-Al composite demonstrated strong selective adsorption of the organic moieties in EDTA-Cu over a broad pH range. Moreover, the oxygen vacancies (Ov) induced by Ca and Al co-doping played a crucial role in the enhanced catalytic performance and efficient removal of EDTA-Cu. These abundant Ov promoted electron transfer and provided numerous surface adsorption sites, facilitating the conversion of O 2 · - to 1 O 2 . Given that 1 O 2 can rapidly degrade organic compounds containing amino and carboxyl groups, it shows excellent potential for the treatment of EDTA-Cu. This study presents a highly active and reusable catalyst based on a Ca-Al doping strategy, offering a promising approach for the removal of organic-heavy metal complexes.
研究领域:
环境科学
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材料科学
·
化学工程
·
水污染控制
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2018
·
IF 3.485
Lei Cao,Jintang Guo,Jianhua Tian,Yang Xu,Miaomiao Hu,Meiyu Wang,Jinjie Fan
Ca/Al-Layered Double Hydroxide (Ca/Al-LDH), was a kind of important anionic clays with broad applications owing to its properties of exchangeable anion and adjustable particle size. In this study, Ca/Al-LDH had been successfully prepared by co-precipitation method, and it was found that the particle size, crystallinity and morphology of Ca/Al-LDH could be tuned via changing ethanol/water ratio of solution. More interestingly, with the increase of the Ca/Al-LDH’s dosage, the different crystal structure of Ca/Al-LDH had promoting effect on the development of the early strength of the cement slurries, however, the change trend of the strength growth rate of various kinds of cement slurries were quite different. Meanwhile, experimental results disclosed that the crystallinity and particle size of Ca/Al-LDH determined its interaction with cement hydration particles. That was likely to lead to a change in tricalcium silicate (C 3 S) and tricalcium aluminate (C 3 A) hydration process of accelerating or retarding under the different Ca/Al-LDH content, thus enabling the early strength development of slurry to exhibit different trends. And this finding could provide further interpretation for the effect of hydrotalcite-like materials on cement hydration process and offer a theoretical exploration for its practical application in the future.
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DOI
高影响因子
危险品化学品经营许可证（带存储）