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Adsorption of toluene, ethylbenzene and xylene isomers on multi-walled carbon nanotubes oxidized by different

Fei YU, Jie MA, Yanqing WU

《环境科学与工程前沿（英文）》 2012年 第6卷 第3期   页码 320-329 doi: 10.1007/s11783-011-0340-4

摘要： Multi-walled carbon nanotubes (MWCNTs) were fabricated and oxidized by different concentrations of sodium hypochlorite (NaOCl) solutions. The untreated MWCNTs and modified MWCNTs were employed as adsorbents to study their characterizations and adsorption performance of toluene, ethylbenzene and xylene isomers (TEX) in an aqueous solution. The physicochemical properties of MWCNTs were greatly affected after oxidation, which influences TEX adsorption capacity. The 3% NaOCl-oxidized MWCNTs shows the greatest enhancement in TEX adsorption, followed by the 30% NaOCl. More interestingly, the 15% NaOCl-oxidized MWCNTs has lower adsorption capacities than untreated MWCNTs. The adsorption mechanism of TEX on treated MWCNTs is attributed to the combined action of hydrophobic interaction, π-π bonding interaction between the aromatic ring of TEX and the oxygen-containing functional groups of MWCNTs and electrostatic interaction. 3% NaOCl solution could not only introduce much oxygen-containing functional groups on MWCNTs, but also lead to less damage for the pore structure. This suggests that the CNTs-3% NaOCl is efficient adsorbent for TEX and that they may possess good potential for TEX removal in wastewater treatment.

关键词： adsorption     toluene     ethylbenzene and xylene isomers (TEX)     multi-walled carbon nanotube     surface oxidation    

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Progress in the research and development of p-xylene liquid phase oxidation process

WANG Lijun, CHENG Youwei, WANG Qinbo, LI Xi

《化学科学与工程前沿（英文）》 2007年 第1卷 第3期   页码 317-326 doi: 10.1007/s11705-007-0058-9

摘要： The process of -xylene liquid phase oxidation to produce purified terephthalic acid (PTA) involves a series of liquid phase radical reactions, chemical absorption, reactive crystallization, and evaporation. A commercial PTA production flow sheet includes a number of unit operations, which construct a complex process system. In this paper, a review of research and development (R&D) works on PTA process carried out in Zhejiang University during recent years is introduced. The works cover the oxidation and crystallization kinetics, gas-liquid mass transfer and evaporation, reactor modeling, database development, novel reactor design, process modeling, simulation, and optimization. The author emphasizes the viewpoint through this case study that chemical reaction engineering should be developed to process system engineering to extend its scope, and particular attention should be paid on reactor and process modeling.

关键词： development     -xylene     Zhejiang University     particular attention     viewpoint    

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Effect of TiO 2 loading on the activity of V/TiO 2 -Al 2 O 3 in the catalytic oxidehydrogenation of ethylbenzene

Xiaohong LI, Wenying LI,

《化学科学与工程前沿（英文）》 2010年 第4卷 第2期   页码 142-146 doi: 10.1007/s11705-009-0233-2

摘要： TiO-AlOmixed oxides with different compositions ranging from 40wt-% to 95wt-% of TiO were prepared by sol-gel method and impregnated with different amounts of VO. Supports and catalysts were characterized by X-ray diffraction (XRD), physisorption, temperature preprogrammed reduction (H-TPR), and ammonia temperature programmed desorption (NH-TPD). TiO content in the support had obvious effect on the crystal structure, texture characteristic, acid property, and catalytic activity in dehydrogenation of ethylbenzene (EB) with carbon dioxide. The highest catalytic activity was acquired when the TiO content was 50 wt-%.

关键词： desorption     different     TiO-AlOmixed     physisorption     ethylbenzene    

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Effect of / molecular structures on pyrolysis performance and heat sink of decalin isomers

《化学科学与工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11705-023-2375-z

摘要： Decalin is considered as an important compound of high-energy-density endothermic fuel, which is an ideal on-board coolant for thermal management of advanced aircraft. However, decalin contains two isomers with a tunable composition, and their effects on the pyrolysis performance, such as the heat sink and coking tendency have not been demonstrated. Herein, we investigated the pyrolysis of decalin isomers, i.e., cis-decalin, trans-decalin and their mixtures (denoted as mix-decalin), in order to clarify the effects of the cis-/trans-structures on the pyrolysis performance of decalin fuels. The pyrolysis results confirmed that conversion of the tested fuels (600–725 °C, 4 MPa) decreased in the order cis-decalin > mix-decalin > trans-decalin. Detailed analyses of the pyrolysis products were used to compare the product distributions from cis-decalin, mix-decalin and trans-decalin, and the yields of some typical components (such as cyclohexene, 1-methylcyclohexene, benzene and toluene) showed significant differences, which could be ascribed to deeper cracking of cis-decalin. Additionally, the heat sinks and coking tendencies of the decalins decreased in the order cis-decalin > mix-decalin > trans-decalin. This work demonstrates the relationship between the cis/trans structures and the pyrolysis performance of decalin, which provides a better understanding of the structure-activity relationships of endothermic hydrocarbon fuels.

关键词： endothermic fuel     decalin     pyrolysis     heat sink     molecular structure    

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C8芳烃异构化催化剂的开发及应用

乔映宾

《中国工程科学》 1999年 第1卷 第1期   页码 73-77

摘要：

文章介绍了SKI系列C8芳烃异构化催化剂研究工作的进展。阐述了催化剂研制开发的创新思路以及该催化剂的优异性能。该催化剂采用丝光沸石固体酸取代常规的卤素酸，因此操作过程中既可省去补氯和碱洗等繁杂过程，又可避免设备腐蚀并改善了操作环境，是一种环境友好的催化剂。该催化剂可使贫对二甲苯或贫对、邻二甲苯的混合C8芳烃异构为接近热力学平衡的C8芳烃，C8芳烃的选择性大于97%，使用寿命可达5年以上。并介绍了该催化剂在引进的七套C8芳烃异构化工业装置上取代了进口催化剂，将该科技成果转化为现实的生产力所取得的成绩。

关键词： 异构化     催化剂     二甲苯    

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Insights into carbon-based materials for catalytic dehydrogenation of low-carbon alkanes and ethylbenzene

《化学科学与工程前沿（英文）》 2023年 第17卷 第11期   页码 1623-1648 doi: 10.1007/s11705-023-2328-6

摘要： Direct dehydrogenation with high selectivity and oxidative dehydrogenation with low thermal limit has been regarded as promising methods to solve the increasing demands of light olefins and styrene. Metal-based catalysts have shown remarkable performance for these reactions, such as Pt, CrOx, Co, ZrOx, Zn and V. Compared with metal-based catalysts, carbon materials with stable structure, rich pore texture and large surface area, are ideal platforms as the catalysts and the supports for dehydrogenation reactions. In this review, carbon materials applied in direct dehydrogenation and oxidative dehydrogenation reactions including ordered mesoporous carbon, carbon nanodiamond, carbon nanotubes, graphene and activated carbon, are summarized. A general introduction to the dehydrogenation mechanism and active sites of carbon catalysts is briefly presented to provide a deep understanding of the carbon-based materials used in dehydrogenation reactions. The unique structure of each carbon material is presented, and the diversified synthesis methods of carbon catalysts are clarified. The approaches for promoting the catalytic activity of carbon catalysts are elaborated with respect to preparation method optimization, suitable structure design and heteroatom doping. The regeneration mechanism of carbon-based catalysts is discussed for providing guidance on catalytic performance enhancement. In addition, carbon materials as the support of metal-based catalysts contribute to exploiting the excellent catalytic performance of catalysts due to superior structural characteristics. In the end, the challenges in current research and strategies for future improvements are proposed.

关键词： carbon materials     dehydrogenation     active sites     mechanism     catalytic performance     support    

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Synthesis, physicochemical characterizations and catalytic performance of Pd/carbon-zeolite and Pd/carbon-CeO

Zeinab JAMALZADEH, Mohammad HAGHIGHI, Nazli ASGARI

《环境科学与工程前沿（英文）》 2013年 第7卷 第3期   页码 365-381 doi: 10.1007/s11783-013-0520-5

摘要： In this work, xylene removal from waste gas streams was investigated via catalytic oxidation over Pd/carbon-zeolite and Pd/carbon-CeO nanocatalysts. Activated carbon was obtained from pine cone chemically activated using ZnCl and modified by H PO . Natural zeolite of clinoptilolite was modified by acid treatment with HCl, while nano-ceria was synthesized via redox method. Mixed supports of carbon-zeolite and carbon-ceria were prepared and palladium was dispersed over them via impregnation method. The prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller surface area (BET), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG) techniques. Characterization of nanocatalysts revealed a good morphology with an average particle size in a nano range, and confirmed the formation of nano-ceria with an average crystallite size below 60 nm. BET analysis indicated a considerable surface area for catalysts (~1000 m ·g ). FTIR patterns demonstrated that the surface groups of synthesized catalysts are in good agreement with the patterns of materials applied in catalyst synthesis. The performance of catalysts was assessed in a low-pressure catalytic oxidation pilot in the temperature range of 100°C–250°C. According to the reaction data, the synthesized catalysts have been shown to be so advantageous in the removal of volatile organic compounds (VOCs), representing high catalytic performance of 98% for the abatement of xylene at 250°C. Furthermore, a reaction network is proposed for catalytic oxidation of xylene over nanocatalysts.

关键词： Pd/carbon-CeO2     Pd/carbon-zeolite     pine cone     ZnCl2     catalytic oxidation     xylene    

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Catalytic process modeling and sensitivity analysis of alkylation of benzene with ethanol over MIL-101(Fe) and MIL-88(Fe)

Ehsan Rahmani, Mohammad Rahmani

《化学科学与工程前沿（英文）》 2020年 第14卷 第6期   页码 1100-1111 doi: 10.1007/s11705-019-1891-3

摘要： A solvothermal method was used to synthesize MIL-101(Fe) and MIL-88(Fe), which were used for alkylation of benzene. The synthesized catalysts were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscope, dynamic light scattering, and BET techniques. Metal-organic frameworks (MOFs) were modeled to investigate the catalytic performance and existence of mass transfer limitations. Calculated effectiveness factors revealed absence of internal and external mass transfer. Sensitivity analysis revealed best operating conditions over MIL-101 at 120°C and 5 bar and over MIL-88 at 142°C and 9 bar.

关键词： MOFs     alkylation     ethylbenzene     catalysts pellet model     kinetic model     sensitivity analysis    

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标题 作者 时间 类型 操作

Adsorption of toluene, ethylbenzene and xylene isomers on multi-walled carbon nanotubes oxidized by different

Fei YU, Jie MA, Yanqing WU

期刊论文

Progress in the research and development of p-xylene liquid phase oxidation process

WANG Lijun, CHENG Youwei, WANG Qinbo, LI Xi

期刊论文

Effect of TiO 2 loading on the activity of V/TiO 2 -Al 2 O 3 in the catalytic oxidehydrogenation of ethylbenzene

Xiaohong LI, Wenying LI,

期刊论文

Effect of / molecular structures on pyrolysis performance and heat sink of decalin isomers

期刊论文

C8芳烃异构化催化剂的开发及应用

乔映宾

期刊论文

Insights into carbon-based materials for catalytic dehydrogenation of low-carbon alkanes and ethylbenzene

期刊论文

Synthesis, physicochemical characterizations and catalytic performance of Pd/carbon-zeolite and Pd/carbon-CeO

Zeinab JAMALZADEH, Mohammad HAGHIGHI, Nazli ASGARI

期刊论文

Catalytic process modeling and sensitivity analysis of alkylation of benzene with ethanol over MIL-101(Fe) and MIL-88(Fe)

Ehsan Rahmani, Mohammad Rahmani

期刊论文