期刊文献+
共找到5,416篇文章
< 1 2 250 >
每页显示 20 50 100
Preparation of Co/S co-doped carbon catalysts for excellent methylene blue degradation
1
作者 Haixu Li Haobo He +7 位作者 Tiannan Jiang Yunfei Du Zhichen Wu Liang Xu Xinjie Wang Xiaoguang Liu Wanhua Yu Wendong Xue 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS 2025年第1期169-181,共13页
S and Co co-doped carbon catalysts were prepared via pyrolysis of MOF-71 and thiourea mixtures at 800℃at a mass ratio of MOF-71 to thiourea of 1:0.1 to effectively activate peroxymonosulfate(PMS)for methylene blue(MB... S and Co co-doped carbon catalysts were prepared via pyrolysis of MOF-71 and thiourea mixtures at 800℃at a mass ratio of MOF-71 to thiourea of 1:0.1 to effectively activate peroxymonosulfate(PMS)for methylene blue(MB)degradation.The effects of two different mixing routes were identified on the MB degradation performance.Particularly,the catalyst obtained by the alcohol solvent evaporation(MOF-AEP)mixing route could degrade 95.60%MB(50 mg/L)within 4 min(degradation rate:K=0.78 min^(-1)),which was faster than that derived from the direct grinding method(MOF-DGP,80.97%,K=0.39 min^(-1)).X-ray photoelectron spectroscopy revealed that the Co-S content of MOF-AEP(43.39at%)was less than that of MOF-DGP(54.73at%),and the proportion of C-S-C in MOF-AEP(13.56at%)was higher than that of MOF-DGP(10.67at%).Density functional theory calculations revealed that the adsorption energy of Co for PMS was -2.94 eV when sulfur was doped as C-S-C on the carbon skeleton,which was higher than that when sulfur was doped next to cobalt in the form of Co-S bond(-2.86 eV).Thus,the C-S-C sites might provide more contributions to activate PMS compared with Co-S.Furthermore,the degradation parameters,including pH and MOF-AEP dosage,were investigated.Finally,radical quenching experiments and electron paramagnetic resonance(EPR)measurements revealed that ^(1)O_(2)might be the primary catalytic species,whereas·O~(2-)might be the secondary one in degrading MB. 展开更多
关键词 advanced oxidation process alcohol solvent evaporation hydrogen bond S and Co co-doped carbon catalysts wastewater remediation
下载PDF
Electron Beam Application for Regeneration of Catalysts Used in Refinery Cracking Units
2
作者 Femando Mantovani Kondo Celina Lopes Duarte +2 位作者 Ivone Mulako Sato Vera Lucia Ribeiro Salvador Wilson Aparecido Parejo Calvo 《Journal of Physical Science and Application》 2016年第3期11-19,共9页
A catalyst is a substance that alters the rate of a reaction. The process of catalysis is essential to the modem day manufacturing industry, mainly in FCC (Fluid Catalytic Cracking) process units. However, long-term... A catalyst is a substance that alters the rate of a reaction. The process of catalysis is essential to the modem day manufacturing industry, mainly in FCC (Fluid Catalytic Cracking) process units. However, long-term exploitation of oil and gas processing catalysts leads to formation of carbon- and sulfur-containing structures of coke and dense products on the catalyst surface. They block reactive catalyst sites and reduce the catalytic activity. The main advantage of radiation processing by EB (electron beam) and gamma rays is chain cracking reaction in crude oil. Otherwise, under exposure to ionize radiation, considerable structure modification of equilibrium silica-alumina catalyst from FCC process may occur, in addition to the removal of impurities. The conditions applied in the irradiation range (20-150 kGy) of gamma rays and EB were not sufficient to alter the structure of the catalyst, whether for removal of the contaminant nickel, a major contaminant of the FCC catalyst, either to rupture of the crystalline structure either for the future reutilization of chemical elements. ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy and EDXRFS (Energy Dispersive X-Ray Fluorescence Spectrometry) analysis were used to characterize and evaluate effects of radiation processing on equilibrium catalysts purification. To evaluate and comprehend the reactive catalyst sites, SEM (Scanning Electron Microscopy) and particle size distribution analyses were carried out. 展开更多
关键词 EB gamma rays FCC process regeneration of catalysts silica-alumina catalyst.
下载PDF
Novel High Performance Ziegler-Natta Catalyst for Ethylene Slurry Polymerization 被引量:9
3
作者 郭子芳 陈伟 +1 位作者 周俊领 杨红旭 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2009年第3期530-534,共5页
A novel high performance MgCl2/TiCl4 catalyst with tetrabutyloxsilicane as electron donor was pre-pared for ethylene slurry polymerization process. The properties of the catalyst such as particle size distribution, ca... A novel high performance MgCl2/TiCl4 catalyst with tetrabutyloxsilicane as electron donor was pre-pared for ethylene slurry polymerization process. The properties of the catalyst such as particle size distribution, catalytic activity, hydrogen responsibility and copolymerization performance were investigated and compared with commercial catalyst (imported catalyst). Copolymerization of ethylene and 1-butylene using the catalyst was stud-ied in a pilot plant. The composition, structure and property of the copolymer were characterized by 13C nuclear magnetic resonance (13C NMR) and gel permeation chromatography-Infrared (GPC-IR), and compared with those of the copolymer obtained from a commercial catalyst. In comparison with the commercial catalyst, the novel cata-lyst had a higher activity (up to 34.6 kg·g-1) and a better particle size distribution (PSD), and produced polymers having higher bulk density (up to 0.37 g·cm-3) with less fine resin. Meanwhile, the novel catalyst showed a higher hydrogen responsibility and better copolymerization performance. The results indicated that the copolymer obtained from the novel catalyst has a higher branch in the high molecular weight fraction and lower branch in the low mo-lecular weight fraction. 展开更多
关键词 Ziegier-Natta catalyst POLYETHYLENE slurry polymerization process structure and properties
下载PDF
100 W-class green hydrogen production from ammonia at a dual-layer electrode containing a Pt-Ir catalyst for an alkaline electrolytic process
4
作者 Donghyun Yoon Sunki Chung +2 位作者 Minjun Choi Eunhyeok Yang Jaeyoung Lee 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第6期352-360,I0009,共10页
Ammonia allows storage and transport of hydrogen over long distances and is an attractive potential hydrogen carrier.Electrochemical decomposition has recently been used for the conversion of ammonia to hydrogen and i... Ammonia allows storage and transport of hydrogen over long distances and is an attractive potential hydrogen carrier.Electrochemical decomposition has recently been used for the conversion of ammonia to hydrogen and is regarded as a future technology for production of CO_(2)-free pure hydrogen.Herein,a heterostructural Pt-Ir dual-layer electrode is developed and shown to achieve successful long-term operation in an ammonia electrolyzer with an anion exchange membrane(AEM).This electrolyzer consisted of eight membra ne electrode assemblies(MEAs)with a total geometric area of 200 cm~2 on the anode side,which resulted in a hydrogen production rate of 25 L h~(-1).We observed the degradation in MEA performance attributed to changes in the anode catalyst layer during hydrogen production via ammonia electrolysis.Furthermore,we demonstrated the relationship between the ammonia oxidation reaction(AOR)and the oxygen evolution reaction(OER). 展开更多
关键词 Ammonia oxidation Dual-layer catalyst Green hydrogen Electrolytic process Oxygen evolution reaction
下载PDF
Development and Commercial Application of Ultra-Low Pressure Naphtha Reforming Technology with Continuous Catalyst Regeneration 被引量:2
5
作者 Ma Aizeng Xu Youchun +2 位作者 Yang Dong Zhang Xinkuan Wang Jieguang 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2013年第4期1-8,共8页
The development history and major technological innovations of the ultra-low pressure naphtha reforming technology with continuous catalyst regeneration in China were introduced.This technology had been adopted by the... The development history and major technological innovations of the ultra-low pressure naphtha reforming technology with continuous catalyst regeneration in China were introduced.This technology had been adopted by the 1.0 Mt/a CCR unit at the Guangzhou Company.The appropriate catalyst was selected to meet the demand of the unit capacity,the feedstock,and the product slate.The design parameters,including the reaction pressure,the octane number of C5+liquid product,the reaction temperature,the space velocity,the hydrogen/oil molar ratio,and the catalyst circulating rate,were chosen based on the study of process conditions and parameters.The commercial test results showed that the research octane number of C5+product reached 104 when the capacity of the CCR unit was 100%and 115%of the design value.The other technical targets attained or exceeded the expected value. 展开更多
关键词 ultra-low pressure continuous catalytic reforming catalyst RegENERATION AROMATICS GASOLINE process NAPHTHA
下载PDF
Progress in Processes and Catalysts for Dehydrogenation of Cyclohexanol to Cyclohexanone
6
作者 Jing Gong Shixin Hou +1 位作者 Yue Wang Xinbin Ma 《Transactions of Tianjin University》 EI CAS 2023年第3期196-208,共13页
The dehydrogenation of cyclohexanol to cyclohexanone is a crucial industrial process in the production of caprolactam and adipic acid, both of which serve as important precursors in nylon textiles. This endothermic re... The dehydrogenation of cyclohexanol to cyclohexanone is a crucial industrial process in the production of caprolactam and adipic acid, both of which serve as important precursors in nylon textiles. This endothermic reaction is constrained by thermodynamic equilibrium and involves a complex reaction network, leading to a heightened focus on catalysts and process design. Copper-based catalysts have been extensively studied and exhibit exceptional low-temperature catalytic performance in cyclohexanol dehydrogenation, with some being commercially used in the industry. This paper specifically concentrates on research advancement concerning active species, reaction mechanisms, factors influencing product selectivity, and the deactivation behaviors of copper-based catalysts. Moreover, a brief introduction to the new processes that break thermodynamic equilibrium via reaction coupling and their corresponding catalysts is summarized here as well. These reviews may off er guidance and potential avenues for further investigations into catalysts and processes for cyclohexanol dehydrogenation. 展开更多
关键词 CYCLOHEXANOL DEHYDROGENATION CYCLOHEXANONE Copper-based catalyst Reaction coupling processes
下载PDF
球形Ziegler-Natta催化剂在中石化环管聚丙烯工艺装置的应用
7
作者 程刘峰 《广东化工》 CAS 2024年第7期14-16,共3页
在中国石化茂名分公司国产第二代环管聚丙烯工艺装置上,采用国产球形Ziegler-Natta催化剂(催化剂1)生产了PPH-T03、N-Z30S和PPR-M55-S三种牌号聚丙烯。研究了球形催化剂在生产三种牌号聚丙烯时的催化剂效率和氢调性,同时分析了各牌号聚... 在中国石化茂名分公司国产第二代环管聚丙烯工艺装置上,采用国产球形Ziegler-Natta催化剂(催化剂1)生产了PPH-T03、N-Z30S和PPR-M55-S三种牌号聚丙烯。研究了球形催化剂在生产三种牌号聚丙烯时的催化剂效率和氢调性,同时分析了各牌号聚丙烯的粉料粒径及产品质量,并将其与另一个国产球形催化剂(催化剂2)进行了对比分析。实验结果表明,与催化剂2相比,两种催化剂生产的聚丙烯在产品质量上相当,但催化剂1的氢调性更加优异,更有利于装置生产高熔融指数产品。 展开更多
关键词 聚丙烯 环管聚丙烯工艺 球形Z-N催化剂 氢调性 高熔融指数
下载PDF
Methane reforming with CO_2 to syngas over CeO_2-promoted Ni/Al_2O_3-ZrO_2 catalysts prepared via a direct sol-gel process 被引量:2
8
作者 Hansheng Li Hang Xu Jinfu Wang 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2011年第1期1-8,共8页
CeO2-promoted Ni/Al2O3-ZrO2 (Ni/Al2O3-ZrO2-CeO2) catalysts were prepared by a direct sol-gel process with citric acid as gelling agent. The catalysts used for the methane reforming with CO2 was studied by infrared s... CeO2-promoted Ni/Al2O3-ZrO2 (Ni/Al2O3-ZrO2-CeO2) catalysts were prepared by a direct sol-gel process with citric acid as gelling agent. The catalysts used for the methane reforming with CO2 was studied by infrared spectroscopy (IR), thermal gravimetric analysis (TGA), microscopic analysis, X-ray diffraction (XRD) and temperature-programmed reduction (TPR). The catalytic performance for CO2 reforming of methane to synthesis gas was investigated in a continuous-flow micro-reactor under atmospheric pressure. TGA, IR, XRD and microscopic analysis show that the catalysts prepared by the direct sol-gel process consist of Ni particles with a nanostructure of around 5 nm and an amorphous-phase composite oxide support. There exists a chemical interaction between metallic Ni particles and supports, which makes metallic Ni well dispersed, highly active and stable. The addition of CeO2 effectively improves the dispersion and the stability of Ni particles of the prepared catalysts, and enhances the adsorption of CO2 on the surface of catalysts. The catalytic tests for methane reforming with CO2 to synthesis gas show that the Ni/Al2O3-ZrO2-CeO2 catalysts show excellent activity and stability compared with the Ni/Al2O3 catalyst. The excellent catalytic activity and stability of the Ni/Al2O3-ZrO2-CeO2 are attributed to the highly, uniformly and stably dispersed small metallic Ni particles, the high reducibility of the Ni oxides and the interaction between metallic Ni particles and the composite oxide supports. 展开更多
关键词 methane reforming with CO2 SYNGAS Ni-based catalyst CEO2 sol-gel process
下载PDF
孔道结构修饰的Ziegler-Natta催化剂设计与高抗冲低缠结UHMWPE的制备 被引量:1
9
作者 刘倩 曹禹 +2 位作者 周琦 穆景山 历伟 《化工学报》 EI CSCD 北大核心 2023年第3期1092-1101,共10页
从SiO_(2)载体孔道修饰的角度出发,向多级孔道中同时引入聚苯乙烯(PS)和聚倍半硅氧烷(POSS),形成功能化复合载体,并用于负载TiCl4,制备SiO_(2)/PS/POSS/TiCl4负载型催化剂。采用热重分析、N2等温吸附脱附、扫描电镜、漫反射红外光谱等... 从SiO_(2)载体孔道修饰的角度出发,向多级孔道中同时引入聚苯乙烯(PS)和聚倍半硅氧烷(POSS),形成功能化复合载体,并用于负载TiCl4,制备SiO_(2)/PS/POSS/TiCl4负载型催化剂。采用热重分析、N2等温吸附脱附、扫描电镜、漫反射红外光谱等手段对修饰前后催化剂的结构进行表征,发现利用苯乙烯的原位聚合能够向SiO_(2)多级孔道,尤其是微孔中引入PS,孔道内PS链段的溶胀行为导致聚合时乙烯传质阻力增大,聚合活性降低。向SiO_(2)多级孔道中引入POSS,由于POSS分子的空间位阻,其只能进入SiO_(2)大孔中,初生态聚乙烯分子链缠结程度降低有限。而将PS与POSS共同引入催化剂各级孔道中,PS与POSS能够产生良性协同作用,能够以高活性制备低缠结的超高分子量聚乙烯,显著提升了产品的抗冲击强度。最后通过降低孔道内TiCl_(4)的负载量,进一步稀释催化剂活性中心,实现聚乙烯活性链解缠结的过程强化。当钛含量降至2.65%时,聚合活性、抗冲击强度和链缠结程度均达到最佳。 展开更多
关键词 ZIegLER-NATTA催化剂 聚乙烯 冲击性能 链缠结 过程强化
下载PDF
PE-UHMW聚合用氧基硅烷内给电子体Ziegler-Natta催化剂的制备及应用 被引量:1
10
作者 吕东昊 王大明 +4 位作者 王永年 李继新 陆震 马子斐 肖波 《工程塑料应用》 CAS CSCD 北大核心 2023年第6期124-128,140,共6页
采用实验室自制的两种复合型氧基硅烷内给电子体:二甲基二(2-酚基乙氧基)硅烷(IED1)和二甲基二(2-氯乙氧基)硅烷(IED2),将两种内给电子体配置Ziegler-Natta催化剂并进行乙烯的催化聚合以制备超高分子量聚乙烯(PE-UHMW)。考察了两种内给... 采用实验室自制的两种复合型氧基硅烷内给电子体:二甲基二(2-酚基乙氧基)硅烷(IED1)和二甲基二(2-氯乙氧基)硅烷(IED2),将两种内给电子体配置Ziegler-Natta催化剂并进行乙烯的催化聚合以制备超高分子量聚乙烯(PE-UHMW)。考察了两种内给电子体加入对Ziegler-Natta催化剂的载钛量、催化剂活性、催化剂的微观形貌及聚合物分子量等因素的影响,并考察催化剂加入量、聚合温度、聚合时间、助催化剂加入量对PE-UHMW聚合效果的影响。由于IED1结构中含有4个含氧基团,电子云密度高于IED2,因此IED1对催化剂活性以及聚合物分子量影响较大。最终确定PE-UHMW聚合工艺条件为:以IED1为内给电子体,催化剂加入量为12 mg/L,IED1与载体氯化镁的物质的量之比为1∶4,聚合温度为75℃,聚合时间为2 h,催化剂中Al/Ti物质的量之比为80。在此工艺条件下催化剂的催化效率为17.1 kg/(g·h),催化剂载钛量为5.8%,PE-UHMW堆密度为0.3 g/cm^(3),PE-UHMW分子量为4.0×10^(6)。 展开更多
关键词 内给电子体 ZIegLER-NATTA催化剂 超高分子量聚乙烯 催化剂配置工艺 聚合生产工艺
下载PDF
A New Catalyst for Hydrogen Transfer Hydrogenation of Acetophenone
11
作者 Pian Pian XU Rong Hui ZHENG +2 位作者 Jing Xing GAO Pei Qing HUANG Hui Lin WAN (Department of Chemistry and Stste Key Laboratory of Physical Chemistry of Solid Surface Xiamen University, Xiamen 361005 ) 《Chinese Chemical Letters》 SCIE CAS CSCD 1997年第3期255-258,共4页
A new C-2-symmetric diamine/diphosphine Ruthenium (II) complex, RuCl2P2N2H4, was used as an excellent catalyst to carry out the catalytic hydrogen transfer reduction of acetophenone. The conversion of acetophenone to ... A new C-2-symmetric diamine/diphosphine Ruthenium (II) complex, RuCl2P2N2H4, was used as an excellent catalyst to carry out the catalytic hydrogen transfer reduction of acetophenone. The conversion of acetophenone to 2-phenylethanol was up to 99% under the following reaction conditions: substrate:Ru:(CH3)(2)CHOK = 200:1:12; reaction temperature of 65 degrees C; reaction time of 2 h; normal pressure. A hydride transfer mechanism was also discussed. 展开更多
关键词 A new catalyst for Hydrogen Transfer Hydrogenation of Acetophenone PRO CHEN WANG
下载PDF
A NEW PROBE FOR IDENTIFYING PROPERTIES OF SUPPORTED METAL AND METAL OXIDE CATALYSTS
12
作者 Shao Ming HUANG Bing Lin HE Institute of Polymer Chemistry,Nankai University Tianjin 300071 《Chinese Chemical Letters》 SCIE CAS CSCD 1991年第9期703-706,共4页
A novel molecular probe for identifying properties of supported transition metals and metal oxides catalysts was established.The catalytic mechanism of transition metals was proposed.
关键词 COH TR A new PROBE FOR IDENTIFYING PROPERTIES OF SUPPORTED METAL AND METAL OXIDE catalystS
下载PDF
乙烯聚合Ziegler-Natta催化剂在聚乙烯管材专用料的应用 被引量:1
13
作者 高金龙 张建纲 +4 位作者 王勇 干昌舒 蒋召财 范江 李婧 《合成材料老化与应用》 CAS 2023年第5期74-76,共3页
JCES催化剂与装置常用催化剂(Ref催化剂)进行小试对比研究,表明JCES催化剂具有良好的活性、优异的氢调性能及共聚性能。采用JCES催化剂用于CX聚合工艺高密度聚乙烯装置,生产聚乙烯管材专用料(牌号为L7100M)。生产结果表明,由Ref催化剂... JCES催化剂与装置常用催化剂(Ref催化剂)进行小试对比研究,表明JCES催化剂具有良好的活性、优异的氢调性能及共聚性能。采用JCES催化剂用于CX聚合工艺高密度聚乙烯装置,生产聚乙烯管材专用料(牌号为L7100M)。生产结果表明,由Ref催化剂切换至JCES催化剂生产过程中进料量平稳无明显波动,参数调整稳定。JCES催化剂的活性及聚合物堆密度与Ref催化剂基本一致,JCES催化剂的氢调敏感性及共聚性能优于Ref催化剂,由JCES催化剂生产的聚合物的分布更加集中,细粉含量比Ref催化剂少。JCES催化剂生产的L7100M产品质量属于优级品,表明JCES催化剂适用于CX工艺生产聚乙烯管材专用料。 展开更多
关键词 ZIegLER-NATTA催化剂 CX工艺 高密度聚乙烯 聚乙烯管材专用料
下载PDF
The Stereoselective Epoxidation by a New Type of Soluble Polymer-Supported Catalysts
14
作者 Wang Yongmei Wang Xin Liu Juyan 《合成化学》 CAS CSCD 2004年第z1期101-101,共1页
关键词 The Stereoselective Epoxidation by a new Type of Soluble Polymer-Supported catalysts
下载PDF
Methane Conversion Using Dielectric Barrier Discharge: Comparison with Thermal Process and Catalyst Effects 被引量:4
15
作者 Antonius Indarto Jae-Wook Choi +1 位作者 Hwaung Lee Hyung Keun Song 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2006年第2期87-92,共6页
The direct conversion of methane using a dielectric barrier discharge has been experimentally studied. Experiments with different values of flow rates and discharge voltages have been performed to investigate the effe... The direct conversion of methane using a dielectric barrier discharge has been experimentally studied. Experiments with different values of flow rates and discharge voltages have been performed to investigate the effects on the conversion and reaction products both qualitatively and quantitatively. Experimental results indicate that the maximum conversion of methane has been 80% at an input flow rate of 5 ml/min and a discharge voltage of 4 kV. Experimental results also show that the optimum condition has occurred at a high discharge voltage and higher input flow rate. In terms of product distribution, a higher flow rate or shorter residence time can increase the selectivity for higher hydrocarbons. No hydrocarbon product was detected using the thermal method, except hydrogen and carbon. Increasing selectivity for ethane was found when Pt and Ru catalysts presented in the plasma reaction. Hydrogenation of acetylene in the catalyst surface could have been the reason for this phenomenon as the selectivity for acetylene in the products was decreasing. 展开更多
关键词 PLASMA dielectric barrier discharge thermal process methane conversion catalyst
下载PDF
Semi-solid A356 alloy slurry for rheocasting prepared by a new process 被引量:3
16
作者 Liu Zheng Liu Xiaomei Mao Weimin 《China Foundry》 SCIE CAS 2013年第3期176-180,共5页
To obtain the semi-solid slurry with uniform and fine structure morphology that satisfies the requirement of rheocasting process, a new process for preparing semi-solid AI alloy slurry was developed, in which local ch... To obtain the semi-solid slurry with uniform and fine structure morphology that satisfies the requirement of rheocasting process, a new process for preparing semi-solid AI alloy slurry was developed, in which local chilling was combined with low superheat pouring and slight electromagnetic stirring (LSPSEMS). The morphology and the size of primary a-AI in the A356 alloy slurry prepared with the new process, i.e., LSPSEMS with local chilling, were investigated using MIAPS image analyzing software, and the grain refinement mechanism was discussed. The results indicate that the semi-solid primary phase consists of particle-like or globular-like a-AI, and the morphology and grain size of primary a-AI in the slurry can be markedly improved by the new process. The fine primary a-AI distributes uniformly in the slurry, which satisfies the requirement of rheocasting. Compared with the alloy prepared by LSPSEMS, the average equal-area-circle grain diameter of primary a-AI in semi-solid A356 alloy ingot prepared by the new process is decreased from 85.6μm to 68.8 μm at the central area, 112.6 μm to 77.6 μm at the transition area and is 84.7 μm in the edge area, respectively. The corresponding shape factor of primary a-AI is increased from 0.78 to 0.83, 0.54 to 0.77 and 0.28 to 0.59, respectively. In addition, the pouring temperature could be suitably raised from 620-630℃ of the traditional process to 650℃ using this technique, which is convenient for practical operation. The mechanism of grain refinement, in the new process, is that the local chilling quickens up the temperature decrease in the center of the melt. The nuclei could not grow up in a short time so the finer grains are formed in the melt. 展开更多
关键词 SEMI-SOLID A356 alloy new process RHEOCASTING
下载PDF
Conversion of Au(Ⅲ)-polluted waste eggshell into functional CaO/Au nanocatalyst for biodiesel production 被引量:3
17
作者 Jiadi Liu Minghuan Liu +5 位作者 Shaoyun Chen Bingqing Wang Jin Chen Da-Peng Yang Shangzhou Zhang Wenxiao Du 《Green Energy & Environment》 SCIE EI CSCD 2022年第2期352-359,共8页
Developing an environmental-friendly and highly active catalyst in transesterification for biodiesel production is of great importance for a more economic biodisel process.Herein,we reported that waste eggshells were ... Developing an environmental-friendly and highly active catalyst in transesterification for biodiesel production is of great importance for a more economic biodisel process.Herein,we reported that waste eggshells were used to adsorb Au(Ⅲ) in water and convert the Au(Ⅲ)-polluted eggshells into the functional nanocatalyst-Ca O/Au for the transesterification reaction between soybean oil and methanol to the preparation of biodiesel.By coupling of Ca O and Au nanoparticles,Ca O/Au nanoparticles showed superior catalytic activity for the transesterification reaction between soybean oil and methanol.An optimum performance was observed over Ca O/Au nanocomposites in a methanol-oil molar ratio at 12:1with catalyst content of 1.0 wt% at 70°C for 3 h.Besides,the catalytic activity of Ca O/Au nanocatalyst was almost unchanged after recycling for 5 times and the yield of biodiesel still kept at 88.9%.The proof-of concept study provided us a sustainable method for utilization of waste eggshells to remedy the metal ions-polluted wastewater and the synthesis of functional nanocomposite for biodiesel production,show great potential application of waste eggshell in adsorption and catalytic reactions. 展开更多
关键词 process Au(Ⅲ) catalyst
下载PDF
Study on the mechanism of coal liquefaction reaction and a new process concept 被引量:1
18
作者 史士东 李文博 +2 位作者 王勇 郭治 李克健 《Journal of Coal Science & Engineering(China)》 2008年第1期119-124,共6页
The coal hydrogenation reaction process is simply considered as three steps.In the first step,the smaller molecules associated with coal structure units are released as some gases and water in the condition of solvent... The coal hydrogenation reaction process is simply considered as three steps.In the first step,the smaller molecules associated with coal structure units are released as some gases and water in the condition of solvent and heating.In this step,some weaker bonds of the coal structure units are ruptured to form free radicals.The radicals are stabi- lized by hydrogen atoms from donor solvent and/or H2.In the second step,chain reaction occurs quickly.In the process of chain reaction,the covalent bonds of coal structure units are attacked by the radicals to form some asphaltenes.In the third step,asphaltenes are hydrogenated form more liquids and some gases.In coal liquefaction,the second step of coal hydrogenation reaction should be controlled to avoid integration of radicals,and the third step of coal hydrogenation should be accelerated to increase the coal conversion and the oil yield.A new concept of coal liquefaction process named as China direct coal lique- faction (CDCL) process is presented based on the mechanism study of coal liquefaction. 展开更多
关键词 coal liquefaction reaction mechanism new process
下载PDF
Stable and efficient metal-biochar supported catalyst:degradation of model pollutants through sulfate radical-based advanced oxidation processes
19
作者 Fermín Delgado Victoria S.Gutierrez +1 位作者 Mariana Dennehy Mariana Alvarez 《Biochar》 2020年第3期319-328,共10页
This study focuses on the synthesis of metal-based biochar catalysts and their catalytic activation of peroxymonosulfate(PMS,HSO5−)for the degradation of three different wastewater model pollutants employing advanced ... This study focuses on the synthesis of metal-based biochar catalysts and their catalytic activation of peroxymonosulfate(PMS,HSO5−)for the degradation of three different wastewater model pollutants employing advanced oxidation processes(AOP).Iron,copper,and two different cobalt-based catalysts were prepared and evaluated.The catalysts were supported on a biochar obtained from the pyrolysis of woody pruning wastes.They were characterized by C,H,and N elemental analysis,X-Ray diffraction(XRD),Fourier-transform infrared spectroscopy(FTIR),and scanning electron microscope(SEM).The metal content in each catalyst was determined by means of atomic absorption spectroscopy(AAS).The degradation reac-tions of benzoic acid(BA),catechol(C),and cinnamic acid(CA)were carried out in a lab scale batch glass reactor and were followed by UV-Visible spectroscopy(UV-Vis).A colorimetric technique was employed to verify the presence of oxidant during the reaction progress.The catalyst/oxidant optimal ratio was determined for the cobalt catalysts.The mineralization degree of the pollutants after the degradations was verified by means of total organic carbon(TOC)content in the residual liquids.After 4 h of reaction,the maximum mineralization was reached when C was treated with a cobalt-based catalyst(>80%),and its stability was evaluated through successive cycles of use. 展开更多
关键词 BIOCHAR Organic pollutants Advanced oxidation processes Sulfate radicals Cobalt catalysts
原文传递
Application of the Solvothermal Process in the Synthesis of High-performance Ag/γ-Al_2O_3 Catalysts
20
作者 唐清 李锐星 +3 位作者 殷澍 Shingo Goto Daisuke Nagai Tsugio Sato 《过程工程学报》 EI CAS CSCD 北大核心 2006年第4期633-638,共6页
Ag/γ-Al2O3 is a kind of promising catalyst with the relatively lower cost compared with those using noble metals,good resistance against catalytic poisoning and excellent behaviour for NOx removal.In the present stud... Ag/γ-Al2O3 is a kind of promising catalyst with the relatively lower cost compared with those using noble metals,good resistance against catalytic poisoning and excellent behaviour for NOx removal.In the present study,Ag/γ-Al2O3 catalysts were synthesized by the solvothermal process and characterized by XRD,TG?DTA,TEM,UV?Vis and FT?IR.It was found that high-performance Ag/γ-Al2O3 catalysts could be synthesized by properly selecting starting materials,controlling the composition of solvent and other reaction conditions.The microstructure evolution of the catalysts was also discussed. 展开更多
关键词 Ag/γ-Al2O3 solvothermal process catalyst MICROSTRUCTURE
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部