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Impregnation of thermoplastic resin in jute fiber mat

LIU Xiaoye, DAI Gance

《化学科学与工程前沿（英文）》 2008年第2卷第2期页码 145-149 doi: 10.1007/s11705-008-0030-3

摘要： Impregnation rate of thermoplastic resin (polypropylene) in jute fiber mat and influence of relative factors on impregnation were studied, aiming to develop the continuous melt impregnation technique and to investigate the effect of impregnation rate and temperature on processing conditions and mechanical properties of natural fiber mat-reinforced thermoplastics. Influence of pressure on porosity of fiber mat and effect of melt viscosity on impregnation rate were also investigated. The modified capillary rheometer was used as apparatus and experimental data were analyzed based on the one-dimension Darcy’s law. Results showed that at a given pressure, the impregnation rate is inversely proportional to melt viscosity and jute fiber mat has higher porosity than glass fiber mat. The architecture, compressibility, permeability and fiber diameter of jute fiber mat were compared with those of glass fiber mat and their effects on impregnation were discussed further. It could be seen that the average diameter of jute fiber is much bigger; the porosity of jute fiber mat is significantly higher and inner bundle impregnation does not exist in jute fiber mat. Therefore, it is not difficult to understand why the impregnation rate in jute fiber mat is 3.5 times higher and permeability is 14 times greater. Kozeny constants of jute and glass fiber mats calculated based on the capillary model are 2950 and 442, respectively.

关键词： polypropylene diameter influence proportional impregnation

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Full scale amendment of a contaminated wood impregnation site with iron water treatment residues

Sanne Skov NIELSEN, Peter KJELDSEN, Rasmus JAKOBSEN

《环境科学与工程前沿（英文）》 2016年第10卷第4期 doi: 10.1007/s11783-016-0842-1

摘要： Iron water treatment residues are a free by-product with high concentration of iron oxides Iron water treatment residues has a large potential for arsenic sorption Soils are highly contaminated by arsenic at wood preservation sites Iron water treatment residues were added to hot spots contaminated with arsenic The addition led to significant decrease in leaching of arsenic from the contaminated soil Iron water treatment residues (Fe-WTR) are a free by-product of the treatment of drinking water with high concentration of iron oxides and potential for arsenic sorption. This paper aims at applying Fe-WTR to a contaminated site, measuring the reduction in contaminant leaching, and discussing the design of delivery and mixing strategy for soil stabilization at field scale and present a cost-effective method of soil mixing by common contractor machinery. Soil contaminated by As, Cr, and Cu at an abandoned wood impregnation site was amended with 0.22% (dw) Fe-WTR. To evaluate the full scale amendment a 100 m test site and a control site (without amendment) were monitored for 14 months. Also soil analysis of Fe to evaluate the degree of soil and Fe-WTR mixing was done. Stabilization with Fe-WTR had a significant effect on leachable contaminants, reducing pore water As by 93%, Cu by 91% and Cr by 95% in the upper samplers. Dosage and mixing of Fe-WTR in the soil proved to be difficult in the deeper part of the field, and pore water concentrations of arsenic was generally higher. Despite water logged conditions no increase in dissolved iron or arsenic was observed in the amended soil. Our field scale amendment of contaminated soil was overall successful in decreasing leaching of As, Cr and Cu. With minor improvements in the mixing and delivery strategy, this stabilization method is suggested for use in cases, where leaching of Cu, Cr and As constitutes a risk for groundwater and freshwater.

关键词： Field experiment Iron oxide Arsenic Stabilization Wood preservation sites

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Characterization and catalytic properties of mesoporous CuO/SBA-16 prepared by different impregnation

DONG Yongli, YUAN Fulong, ZHU Yujun, ZHAO Lina, CAI Zhicheng

《化学科学与工程前沿（英文）》 2008年第2卷第2期页码 150-154 doi: 10.1007/s11705-008-0036-x

摘要： CuO/SBA-16 catalysts were prepared by two different routes – the conventional impregnation method and the modified impregnation method with pH adjustment. These catalysts were characterized by X-ray diffraction (XRD), atomic absorption spectrometry (AAS), N physisorption and hydrogen temperature programmed reduction (H-TPR) measurements which reveal that the cubic cage-like () pore structure of the parent SBA-16 molecule sieves was well maintained throughout the synthesis. After introduction of Cu, a different CuO dispersion exists on these catalysts. The CuO/SBA-16 prepared by modified impregnation method has a single highly dispersed CuO which is considered as a highly efficient species for hydroxylation of phenol with HO. CuO/SBA-16 prepared by the conventional impregnation method shows the presence of bulk CuO species which is undesirable for this reaction.

关键词： different CuO/SBA-16 temperature physisorption introduction

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Phosphorous removal from wastewater by lanthanum modified Y zeolites

Weikang ZHANG, Ye TIAN

《化学科学与工程前沿（英文）》 2015年第9卷第2期页码 209-215 doi: 10.1007/s11705-014-1448-4

摘要： The adsorption capacities of Y zeolite and La (III)-modified Y zeolite were studied. A series of La(III)-modified Y zeolites with different La/Y zeolite mass ratios were characterized by X-ray diffraction, X-ray fluorescence and Brunauer-Emmett-Teller surface area analysis. Batch experiments were conducted to evaluate the effects of various experimental parameters, such as pH, ionic strength, coexisting anions ( , Cl , and ) and temperature, on the phosphate adsorption. The capacity of the La (III)-modified Y zeolite to remove phosphate increased as the La/Y zeolite mass ratio increased and after 4 h, a phosphate removal efficiency of 95% was achieved for a La/Y zeolite mass ratio of 0.10. The equilibrium adsorption isotherm data correlated better to the Langmuir model than the Freundlich model and the data followed a pseudo-second-order kinetic equation.

关键词： phosphate removal wastewater lanthanum impregnation Y zeolites

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A novel strategy for the construction of silk fibroin–SiO composite aerogel with enhanced mechanical property and thermal insulation performance

《化学科学与工程前沿（英文）》 2023年第17卷第3期页码 288-297 doi: 10.1007/s11705-022-2222-7

摘要： The practical application of silica aerogels is an enormous challenge due to the difficulties in improving both mechanical property and thermal insulation performance. In this work, silk fibroin was used as scaffold to improve the mechanical property and thermal insulation performance of silica aerogels. The ungelled SiO₂ precursor solution was impregnated into silk fibroin to prepare silk fibroin–SiO₂ composite aerogels via sol−gel method followed by freeze-drying. By virtue of the interfacial hydrogen-bonding interactions and chemical reactions between silk fibroin and silica nanoparticles, SiO₂ was well-dispersed in the silk fibroin aerogel and composite aerogels exhibited enhanced mechanical property. By increasing the loading of silk fibroin from 15 wt % to 21 wt %, the maximum compressive stress was enhanced from 0.266 to 0.508 MPa when the strain reached 50%. The thermal insulation performance of the composite aerogels was improved compared with pure silica aerogel, as evidenced that the thermal conductivity was decreased from 0.0668 to 0.0341 W∙m^‒1∙K^‒1. Moreover, the composite aerogels exhibited better hydrophobicity and fire retardancy compared to pure silica aerogel. Our work provides a novel approach to preparing silk fibroin–SiO₂ composite aerogels with enhanced mechanical property and thermal insulation performance, which has potential application as thermal insulation material.

关键词： silica aerogel silk fibroin impregnation thermal insulation mechanical property

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Catalytic oxidative desulfurization of gasoline using phosphotungstic acid supported on MWW zeolite

Hanlu Wang, Idris Jibrin, Xingye Zeng

《化学科学与工程前沿（英文）》 2020年第14卷第4期页码 546-560 doi: 10.1007/s11705-019-1842-z

摘要： Catalysts for the desulfurization of gasoline samples were synthesized via the immobilization of well-dispersed phosphotungstic acid (HPW) on Mobil composition of matter-twenty-two (MWW) zeolite. Characterization results indicated that these catalysts possess a mesoporous structure with the retention of the Keggin structure of immobilized HPW. Relevant reaction parameters inﬂuencing sulfur removal were systematically investigated, including HPW loading, catalyst dosage, temperature, initial S-concentration, molar ratio of oxidant to sulfide (O/S), volume ratio of MeCN to model oil (Ext./oil), and sulfide species. The 40 wt-% HPW/MWW catalyst exhibited the highest catalytic activity with 99.6% dibenzothiophene sulfur removal from prepared samples. The 40 wt-% HPW/MWW catalyst was recycled four times and could be easily regenerated. Finally, as an exploratory study, straight-run-gasoline and fluid catalytic cracking gasoline were employed to accurately evaluate the desulfurization performance of 40 wt-% HPW/MWW. Our research provides new insights into the development and application of catalysts for desulfurization of gasoline.

关键词： oxidative desulfurization phosphotungstic acid MWW wet impregnation adsorption energy

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Effect of Fe content on FeMn catalysts for light alkenes synthesis

ZHOU Jun, CHU Wei, ZHANG Hui, XU Huiyuan, ZHANG Tao

《化学科学与工程前沿（英文）》 2008年第2卷第3期页码 315-318 doi: 10.1007/s11705-008-0050-z

摘要： The effect of Fe content on FeMn/MgO catalysts for light alkenes synthesis through CO hydrogenation was investigated. Catalysts were prepared by a conventional co-impregnation method, characterized using BET, X-ray powder diffraction (XRD) and Temperature-programmed reduction (H-TPR) techniques. High activity was obtained over the catalyst with 9 wt-% Fe content, over which CO conversion and the selectivity of C–C reached 91.36% and 58.48%, respectively. With the increase of Fe content, both the conversion and the selectivity were improved within a certain range and then decreased. The results show that the surface area of the catalyst played an important role in the catalytic reaction. With the increase of Fe loading, the interaction action between Fe and Mn was enhanced and FeMn solid solution was formed.

关键词： conventional co-impregnation increase conversion loading H-TPR

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Chitosan/polyethylene glycol impregnated activated carbons: Synthesis, characterization and adsorption performance

Ehsan Salehi, Fereshteh Soroush, Maryam Momeni, Aboulfazl Barati, Ali Khakpour

《化学科学与工程前沿（英文）》 2017年第11卷第4期页码 575-585 doi: 10.1007/s11705-017-1650-2

摘要： Novel modified activated carbons (ACs) with enhanced adsorptive properties were obtained coating by chitosan (CS), polyethylene glycol (PEG) and blends of the two polymers (0:1, 1:0, 1:1, 1:2 and 2:1 wt/wt) on ACs by an impregnation technique. The adsorption performances of the pristine, acidified and polymer-impregnated ACs were studied using methylene blue as a model adsorbate. The adsorbents were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy and abrasion hardness tests. The average coating thicknesses were between 10 to 23 microns. The pore sizes, pore densities and pore capacities of the activated carbons increased as the wt-% PEG in the coating increased. The highest adsorption capacity (424.7 mg/g) was obtained for the chitosan-coated ACs and this adsorption was well described by the Langmuir isotherm model. The kinetic results were best described by the pseudo-second-order kinetic model. The highest rate constant was obtained with the ACs modified with the CS:PEG (2:1) coating and this result was almost 2.6 times greater than that of the unmodified ACs. The CS/PEG impregnated ACs also displayed superior hardness (~90%), compared to unmodified ACs (~85%). Overall the chitosan had a greater effect on improving adsorption capacity whereas the polyethylene glycol enhanced the adsorption rate.

关键词： carbon biocomposites impregnation chitosan polyethylene glycol image processing

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Characterization and performance of V

Caiting LI, Qun LI, Pei LU, Huafei CUI, Guangming ZENG

《环境科学与工程前沿（英文）》 2012年第6卷第2期页码 156-161 doi: 10.1007/s11783-010-0295-x

摘要： A series of CeO supported V O catalysts with various loadings were prepared with different calcination temperatures by the incipient impregnation. The catalysts were evaluated for low temperature selective catalytic reduction (SCR) of NO with ammonia (NH ). The effects of O and SO on catalytic activity were also studied. The catalysts were characterized by specific surface areas (S ) and X–ray diffraction (XRD) methods. The experimental results showed that NO conversion changed significantly with the different V O loading and calcination temperature. With the V O loading increasing from 0 to 10 wt%, NO conversion increased significantly, but decreased at higher loading. The optimum calcination temperature was 400°C. The best catalyst yielded above 80% NO conversion in the reaction temperature range of 160°C–300°C. The formation of CeVO on the surface of catalysts caused the decrease of redox ability.

关键词： V₂O₅/CeO₂ catalysts NH₃-SCR (selective catalytic reduction) the incipient impregnation low temperatures