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Plasma-enabled sensing of urea and related amides on polyaniline

Harinarayanan Puliyalil,Petr Slobodian,Michal Sedlacik,Ruhan Benlikaya,Pavel Riha,Kostya (Ken) Ostrikov,Uroš Cvelbar

《化学科学与工程前沿（英文）》 2016年第10卷第2期页码 265-272 doi: 10.1007/s11705-016-1570-6

摘要： The atmospheric pressure plasma jet (APPJ) was used to enhance the sensitivity of industrially important polyaniline (PANI) for detection of organic vapors from amides. The gas sensing mechanism of PANI is operating on the basis of reversible protonation or deprotonation, whereas the driving force to improve the sensitivity after plasma modifications is unknown. Herein we manage to solve this problem and investigate the sensing mechanism of atmospheric plasma treated PANI for vapor detection of amides using urea as a model. The results from various analytical techniques indicate that the plausible mechanism responsible for the improved sensitivity after plasma treatment is operating through a cyclic transition state formed between the functional groups introduced by plasma treatment and urea. This transition state improved the sensitivity of PANI towards 15 ppm of urea by a factor of 2.4 times compared to the non-treated PANI. This plasma treated PANI is promising for the improvement of the sensitivity and selectivity towards other toxic and carcinogenic amide analytes for gas sensing applications such as improving material processing and controlling food quality.

关键词： gas sensing urea PANI amides plasma

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Design guidelines for urea hydrolysers for ammonia demand of the SCR DENOX project in coal-fired power

Peng ZHENG, Xuan YAO, Wei ZHENG

《能源前沿（英文）》 2013年第7卷第1期页码 127-132 doi: 10.1007/s11708-012-0225-7

摘要： Ammonia is highly volatile and will present substantial environmental and operation hazards when leaking into the air. However, ammonia is the most common reactant in the DENOX project to eliminate NO in the flue gas. The storage and transportation of liquid ammonia has always been a dilemma of the power plant. Urea is a perfect substitute source for ammonia in the plant. Urea hydrolysis technology can easily convert urea into ammonia with low expense. Presently, there is still no self-depended mature urea hydrolysis technology for the DENOX project in China; therefore, this paper proposes several guidelines to design the urea hydrolyser by theoretical analysis. Based on theoretical analysis, a simulation model is built to simulate the chemical reaction in the urea hydrolyser and is validated by the operational data of the commercial hydrolyser revealed in the literature. This paper endeavors to propose suggestions and guidelines to develop domestically urea hydrolysers in China.

关键词： urea hydrolyser ammonia selective catalytic reduction (SCR)

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Synthesis of mono and bis-4-methylpiperidiniummethyl-urea as corrosion inhibitors for steel in acidic

Abbas TEIMOURI, Nasrin SOLTANI, Alireza Najafi CHERMAHINI

《化学科学与工程前沿（英文）》 2011年第5卷第1期页码 43-50 doi: 10.1007/s11705-010-0532-7

摘要： Mono and bis-4-methylpiperidiniummethyl urea were synthesized, characterized and used as new corrosion inhibitors of mild steel in the acidic media. Inhibitory effect of two compounds on mild steel surface in the 1 mol·L sulphuric acid has been studied by a series of techniques, such as potentiodynamic polarization, weight loss and quantum chemical calculation methods. Potentiodynamic polarization measurements showed that two inhibitors are mixed type. All measurements showed that inhibition efficiencies enhanced with increase of inhibitor concentration. This reveals that inhibitive actions of inhibitors were mainly due to adsorption on mild steel surface. Density functional (DFT) calculations have been carried out for the title compounds by performing HF and DFT levels of theory using the standard 6-31G* basis set.

关键词： corrosion inhibitors mild steel acidic medium theoretical studies DFT

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modification of broom sorghum-based activated carbon via functionalization with triethylenetetramine and urea

Elaheh Mehrvarz, Ali A. Ghoreyshi, Mohsen Jahanshahi

《化学科学与工程前沿（英文）》 2017年第11卷第2期页码 252-265 doi: 10.1007/s11705-017-1630-6

摘要： A new type of activated carbon (AC) was synthesized using broom sorghum stalk as a low cost carbon source through chemical activation with H PO and KOH. The AC obtained by KOH had the largest BET surface area of 1619 m ·g and the highest micropore volume of 0.671 cm ·g . CO adsorption was enhanced by functionalizing the AC with two different amines: triethylenetetramine (TETA) and urea. The structure of the prepared ACs was characterized by Brunauer-Emmett-Teller method, scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and acid-base Boehm titration analyses. The adsorption behavior of CO onto raw and amine-functionalized ACs was investigated in the temperature range of 288–308 K and pressures up to 25 bar. The amount of CO uptake at 298 K and 1 bar achieved by AC-TETA and AC-urea was 3.22 and 2.33 mmol·g which shows a 92% and 40% improvement compared to pristine AC (1.66 mmol·g ), respectively. Among different model isotherms used to describe the adsorption equilibria, Sips isotherm presented a perfect fit in all cases. Gas adsorption kinetic study revealed a fast kinetics of CO adsorption onto the ACs. The evaluation of the isosteric heat of adsorption demonstrated the exothermic nature of the CO adsorption onto unmodified and modified samples.

关键词： activated carbon broom sorghum functionalization CO₂ capture

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Synthesis of magnetic Pb/Fe

Hualiang AN, Xinqiang ZHAO, Zhiguang JIA, Changcheng WU, Yanji WANG

《化学科学与工程前沿（英文）》 2009年第3卷第2期页码 215-218 doi: 10.1007/s11705-009-0055-2

摘要： To facilitate the recovery of Pb/SiO catalyst, magnetic Pb/Fe O /SiO samples were prepared separately by emulsification, sol-gel and incipient impregnation methods. The catalyst samples were characterized by means of X-ray diffraction and N adsorption-desorption, and their catalytic activity was investigated in the reaction for synthesizing propylene carbonate from urea and 1,2-propylene glycol. When the gelatin was applied in the preparation of Fe O at 60°C and the pH value was controlled at 4 in the preparation of Fe O /SiO , the Pb/Fe O /SiO sample shows good catalytic activity and magnetism. Under the reaction conditions of a reaction temperature of 180°C, reaction time of 2 h, catalyst percentage of 1.7 wt-% and a molar ratio of urea to PG of 1∶4, the yield of propylene carbonate attained was 87.7%.

关键词： Pb/Fe₃O₄/SiO₂ magnetic particle urea 1 2-propylene glycol propylene carbonate

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Synthesis of porous carbon from orange peel waste for effective volatile organic compounds adsorption: role of typical components

《化学科学与工程前沿（英文）》 2023年第17卷第7期页码 942-953 doi: 10.1007/s11705-022-2264-x

摘要： Volatile organic compounds have posed a serious threat to the environment and human health, which require urgent and effective removal. In recent years, the preparation of porous carbon from biomass waste for volatile organic compounds adsorption has attracted increasing attention as a very cost-effective and promising technology. In this study, porous carbon was synthesized from orange peel by urea-assisted hydrothermal carbonization and KOH activation. The role of typical components (cellulose, hemicellulose, and lignin) in pore development and volatile organic compounds adsorption was investigated. Among the three components, hemicellulose was the major contributor to high porosity and abundant micropores in porous carbon. Higher hemicellulose content led to more abundant –COOR, amine-N, and pyrrolic/pyridonic-N in the derived hydrochar, which were favorable for porosity formation during activation. In this case, the toluene adsorption capacity of the porous carbon improved from 382.8 to 485.3 mg·g^–1. Unlike hemicellulose, cellulose reduced the >C=O, amine-N, and pyrrolic/pyridonic-N content of the hydrochar, which caused porosity deterioration and worse toluene adsorption performance. Lignin bestowed the hydrochar with slightly increased –COOR, pyrrolic/pyridonic-N, and graphitic-N, and reduced >C=O, resulting in comparatively poor porosity and more abundant micropores. In general, the obtained porous carbon possessed abundant micropores and high specific surface area, with the highest up to 2882 m²·g^–1. This study can provide guidance for selecting suitable biomass waste to synthesize porous carbon with better porosity for efficient volatile organic compounds adsorption.

关键词： biomass waste porous carbon feedstock composition urea-assisted hydrothermal carbonization toluene adsorption N-doped hydrochar