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Conversion of polyethylene to gasoline: Influence of porosity and acidity of zeolites

《能源前沿（英文）》   页码 763-774 doi: 10.1007/s11708-023-0897-1

摘要： Plastic waste is causing serious environmental problems. Developing efficient, cheap and stable catalytic routes to convert plastic waste into valuable products is of great importance for sustainable development, but remains to be a challenging task. Zeolites are cheap and stable, but they are usually not efficient for plastic conversion at a low temperature. Herein a series of microporous and mesoporous zeolites were used to study the influence of porosity and acidity of zeolite on catalytic activity for plastics conversion. It was observed that H-Beta zeolite was an efficient catalyst for cracking high-density polyethylene to gasoline at 240 °C, and the products were almost C4–C12 alkanes. The effect of porosity and acidity on catalytic performance of zeolites was evaluated, which clearly visualized the good performance of H-Beta due to high surface area, large channel system, large amount accessible acidic sites. This study provides very useful information for designing zeolites for efficient conversion of plastics.

关键词： plastics conversion     polyethylene     zeolites     acidity     porosity    

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Precise regulation of acid pretreatment for red mud SCR catalyst: Targeting on optimizing the acidity

《环境科学与工程前沿（英文）》 2022年 第16卷 第7期 doi: 10.1007/s11783-021-1447-x

摘要：

• The optimum SCR activity was realized by tuning the acid pretreatment.

关键词： Air pollution control     Nitrogen oxides     Selective catalytic reduction     Red mud     Solid waste utilization    

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Enhanced CuCl dispersion by regulating acidity of MCM-41 for catalytic oxycarbonylation of ethanol to

Pengzhen CHEN, Shouying HUANG, Jijie ZHANG, Shengping WANG, Xinbin MA

《化学科学与工程前沿（英文）》 2015年 第9卷 第2期   页码 224-231 doi: 10.1007/s11705-014-1447-5

摘要： CuCl supported on molecular sieves has attracted increasing attention in catalyzing oxidative carbonylation of ethanol to diethyl carbonate. Mesoporous MCM-41 has been widely used as catalyst support due to its large surface area and well defined mesoporous structure. Considering its intrinsic weak acidity, MCM-41 was modified by a simple impregnation method to incorporate Al. The incorporation of Al components resulted in the high dispersion of Cu species and the increase of acid sites without changing the mesoporous structure of MCM-41, and thus enhanceed the catalytic activity of CuCl/MCM-41for diethyl carbonate synthesis.

关键词： MCM-41     acidity     oxidative carbonylation     diethyl carbonate    

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Reductive amination of -hexanol to -hexylamine over Ni–Ce/-AlO catalysts

《化学科学与工程前沿（英文）》 2023年 第17卷 第1期   页码 82-92 doi: 10.1007/s11705-022-2181-z

摘要： The amination of alkyl alcohols is one of the most promising paths in synthesis of aliphatic amines. Herein, cerium doped nickel-based catalysts were synthesized and tested in a gas-phase amination of n-hexanol to n-hexylamine. It was found that the activity of the Ni/γ-Al2O3 catalyst is significantly improved by doping an appropriate amount of cerium. The presence of cerium effectively inhibits the agglomeration of nickel particle, resulting in better Ni dispersion. As Ni particle size plays critical role on the catalytic activity, higher turnover frequency of n-hexanol amination was achieved. Cerium doping also improves the reduction ability of nickel and enhances the interactions between Ni and the catalyst support. More weak acid sites were also found in those cerium doped catalysts, which promote another key step—ammonia dissociative adsorption in this reaction system. The overall synergy of Ni nanoparticles and acid sites of this Ni–Ce/γ-Al2O3 catalyst boosts its superior catalytic performance in the amination of n-hexanol.

关键词： amination     alcohol     cerium     nickel     acidity     interaction    

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Vanadium(IV) solvent extraction enhancement in high acidity using di-(2-ethylhexyl)phosphoric acid with

《化学科学与工程前沿（英文）》 2023年 第17卷 第1期   页码 56-67 doi: 10.1007/s11705-022-2185-8

摘要： Separation of vanadium from black shale leaching solution at low pH is very meaningful, which can effectively avoid the generation of alkali neutralization slag and the resulting vanadium loss. In this study, coordination mechanism of vanadium in acid leaching solution at low pH was investigated with the intervention of chloride ions. Under the conditions of pH 0.8, di-(2-ethylhexyl)phosphoric acid concentration of 20%, phase ratio of 1:2, and extraction time of 8 min, the vanadium extraction could reach 80.00%. The Fourier transform infrared and electrospray ionization results reveal that, despite the fact that the chloride ion in the leachate could significantly promote vanadium extraction, the chloride ion does not enter the organic phase, indicating an intriguing phenomenon. Among Cl−–V, SO42−–V, and H2O–V, the V–Cl bond is longer and the potential difference between coordinate ions and vanadium is smaller. Therefore, VO2+ gets easily desorbed with chloride ions and enter the organic phase. At the same time, the hydrogen ions of di-(2-ethylhexyl)phosphoric acid also enter the water phase more easily, which reduces the pH required for the extraction reaction.

关键词： vanadium     black shale     solvent extraction     high acidity extraction    

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Effects of support acidity on the reaction mechanisms of selective catalytic reduction of NO by CH

Shicheng XU, Junhua LI, Dong YANG, Jiming HAO

《环境科学与工程前沿（英文）》 2009年 第3卷 第2期   页码 186-193 doi: 10.1007/s11783-009-0016-5

摘要： The reaction mechanisms of selective catalytic reduction (SCR) of nitric oxide (NO) by methane (CH ) over solid superacid-based catalysts were proposed and testified by DRIFTS studies on transient reaction as well as by kinetic models. Catalysts derived from different supports would lead to different reaction pathways, and the acidity of solid superacid played an important role in determining the reaction mechanisms and the catalytic activities. Higher ratios of Br?nsted acid sites to Lewis acid sites would lead to stronger oxidation of methane and then could facilitate the step of methane activation. Strong Br?nsted acid sites would not necessarily lead to better catalytic performance, however, since the active surface NO species and the corresponding reaction routes were determined by the overall acidity strength of the support. The reaction routes where NO moiety was engaged as an important intermediate involved moderate oxidation of methane, the rate of which could determine the overall activity. The reaction involving NO moiety was likely to be determined by the step of reduction of NO. Therefore, to enhance the SCR activity of solid superacid catalysts, reactions between appropriate couples of active NO species and activated hydrocarbon intermediates should be realized by modification of the support acidity.

关键词： selective catalytic reduction (SCR)     nitric oxide (NO)     methane     support acidity     Br?nsted acid sites     NOy species    

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Modification of acidity of Mo-Fe/HZSM-5 zeolite via argon plasma treatment

ZHU Xinli, YU Kailu, CHENG Dangguo, XIA Qing, LIU Changjun, ZHANG Yueping

《化学科学与工程前沿（英文）》 2008年 第2卷 第1期   页码 55-58 doi: 10.1007/s11705-008-0005-4

摘要： The NH-TPD characterization was conducted to confirm that the acidity of Mo-Fe/HZSM-5 zeolite could be selectively modified via the glow discharge plasma treatment. The plasma catalyst treatment could totally change the distribution of aromatic products with higher methane conversion compared to the untreated catalyst. Some polycyclic aromatics such as anthracene, pyrene and phenanthrene were also produced over the plasma treated catalyst, in addition to benzene, toluene and naphthalene, which were normally obtained over the untreated catalyst.

关键词： phenanthrene     Mo-Fe/HZSM-5     conversion     glow discharge     polycyclic    

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Synthesis of boron modified CoMo/Al

Hui Shang, Chong Guo, Pengfei Ye, Wenhui Zhang

《化学科学与工程前沿（英文）》 2021年 第15卷 第5期   页码 1088-1098 doi: 10.1007/s11705-020-1969-y

摘要： Catalytic hydrodesulfurization (HDS) technique is widely used for clean gasoline production. However, traditional HDS catalyst (CoMo/ -Al O ) exhibits high hydrogenation performance of olefins (HYDO), resulting in the loss of gasoline octane number. To achieve high HDS/HYDO ratio, the key issue is to reduce the interaction between active metals and the support, therefore, in this research, the modified CoMo/ -Al O catalysts with various boron amounts were investigated under traditional or microwave heating. The effects of preparing methods as well as boron amounts on the active phase, acidic properties and HDS catalytic activities were examined. Results show that the modification, especially under microwave treatment, can significantly weaken the interaction between the active component and the support by enlarging the surface area and pore diameter, and reducing the acidity of the support. As a result, the stacking numbers of MoS slabs were obviously improved by the modification and microwave treatment, contributing to higher edge/rim ratio, and resulting in higher HDS performance and selectivity to olefin.

关键词： CoMo catalyst     boron modification     surface acidity     microwave heating     selective hydrodesulfurization    

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A pyrazine based metal-organic framework for selective removal of copper from strongly acidic solutions

《环境科学与工程前沿（英文）》 2023年 第17卷 第3期 doi: 10.1007/s11783-023-1633-0

摘要：

● pz-UiO-66 was synthesized facilely by a solvothermal method.

关键词： Pyrazine     Metal-organic frameworks     Copper removal     Strong acidity     High selectivity    

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Benzenesulfonic acid-grafted UIO-66 with improved hydrophobicity as a stable Brønsted acid catalyst

《化学科学与工程前沿（英文）》 2023年 第17卷 第10期   页码 1389-1398 doi: 10.1007/s11705-022-2285-5

摘要： Hydrothermal and catalytic stability of UIO-66 MOFs with defective structures are critical aspects to be considered in their catalytic applications, especially under the conditions involving water, moisture and/or heat. Here, we report a facile strategy to introduce the macromolecular acid group to UIO-66 to improve the stability of the resulting UIO-66−PhSO3H MOF in aqueous phase catalysis. In detail, UIO-66−PhSO3H was obtained by grafting benzenesulfonic acid on the surface of the pristine UIO-66 to introduce the hydrophobicity, as well as the Brønsted acidity, then assessed using catalytic hydrolysis of cyclohexyl acetate (to cyclohexanol) in water. The introduction of hydrophobic molecules to UIO-66 could prevent the material from being attacked by hydroxyl polar molecules effectively, explaining its good structural stability during catalysis. UIO-66−PhSO3H promoted the conversion of cyclohexyl acetate at ca. 87%, and its activity and textural properties were basically intact after the cyclic stability tests. The facile modification strategy can improve the hydrothermal stability of UIO-66 significantly, which can expand its catalytic applications in aqueous systems.

关键词： metal−organic frameworks (MOFs)     UIO-66     hydrolysis of cyclohexyl acetate     hydrophobicity     Brønsted acidity    

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Organic nitrogen in PM

Qian ZHANG,Fengkui DUAN,Kebin HE,Yongliang MA,Haiyan LI,Takashi KIMOTO,Aihua ZHENG

《环境科学与工程前沿（英文）》 2015年 第9卷 第6期   页码 1004-1014 doi: 10.1007/s11783-015-0799-5

摘要： Nitrogenous species, as important chemical components in PM , include organic nitrogen (ON) and inorganic nitrogen (IN), both of which have potential effects on human health, climate change and visibility degradation. In this study, we analyzed total nitrogen (TN) by CHN Elemental analyzer and inorganic nitrogen by ion chromatography (IC) respectively to obtain ON by calculating the difference between TN and IN. The results show that the mean ON concentrations in winter and summer are both 2.86 μg·m , ten times higher than other places reported on average. ON contributes about 20%–30% to TN on average in both seasons, presenting higher contribution in summer. N:C ratios are much higher in summer than winter. ON sources or formation were strengthened by heavy PM pollution loads, especially sensitive to sulfate. ON concentrations are higher at night in the both seasons, however with distinguished day and night difference patterns influenced by relative humidity (RH) conditions. In winter, ON concentrations increase with RH on average through low RH values to high RH values. The variations are far larger than the ones caused by day and night difference. However in summer, day and night difference dominates the variations of ON concentrations at low RH values, and RH conditions promote ON concentrations increase significantly only at high RH values. Dust related source and anthropogenic emission related secondary source are identified as important sources for ON. At heavy pollution loads, ON sources are more of secondary formation, possibly strengthened by combination influence of RH and acidity increase.

关键词： organic nitrogen     N:C ratio     secondary     day and night variation     relative humidity (RH)     acidity    

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标题 作者 时间 类型 操作

Conversion of polyethylene to gasoline: Influence of porosity and acidity of zeolites

期刊论文

Precise regulation of acid pretreatment for red mud SCR catalyst: Targeting on optimizing the acidity

期刊论文

Enhanced CuCl dispersion by regulating acidity of MCM-41 for catalytic oxycarbonylation of ethanol to

Pengzhen CHEN, Shouying HUANG, Jijie ZHANG, Shengping WANG, Xinbin MA

期刊论文

Reductive amination of -hexanol to -hexylamine over Ni–Ce/-AlO catalysts

期刊论文

Vanadium(IV) solvent extraction enhancement in high acidity using di-(2-ethylhexyl)phosphoric acid with

期刊论文

Effects of support acidity on the reaction mechanisms of selective catalytic reduction of NO by CH

Shicheng XU, Junhua LI, Dong YANG, Jiming HAO

期刊论文

Modification of acidity of Mo-Fe/HZSM-5 zeolite via argon plasma treatment

ZHU Xinli, YU Kailu, CHENG Dangguo, XIA Qing, LIU Changjun, ZHANG Yueping

期刊论文

Synthesis of boron modified CoMo/Al

Hui Shang, Chong Guo, Pengfei Ye, Wenhui Zhang

期刊论文

A pyrazine based metal-organic framework for selective removal of copper from strongly acidic solutions

期刊论文

Benzenesulfonic acid-grafted UIO-66 with improved hydrophobicity as a stable Brønsted acid catalyst

期刊论文

Organic nitrogen in PM

Qian ZHANG,Fengkui DUAN,Kebin HE,Yongliang MA,Haiyan LI,Takashi KIMOTO,Aihua ZHENG

期刊论文