scholarly journals Effect of Support on the Performance of CoMoRe Catalyst in Thiophene and Benzothiophene Hydrodesulfurization

2019 ◽  
Vol 70 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Rami Doukeh ◽  
Mihaela Bombos ◽  
Daniela Popovici ◽  
Minodora Pasare ◽  
Ion Bolocan
Keyword(s):  
Aqueous Solutions ◽  
Pore Size Distribution ◽  
Pore Volume ◽  
Impregnation Method ◽  
Acidic Properties ◽  
Dimethyl Disulphide ◽  
Temperature And Pressure ◽  
Benzothiophene Hydrodesulfurization ◽  
Effect Of Support ◽  
Selection Of

This work is aimed at selection of a suitable support for CoMoRe catalyst in hydrodesulfurization (HDS) of thiophenes. g-Al2O3 and g-Al2O3-HMS were used as a support for CoMoRe catalyst with 4%Co, 8%Mo and 0.5%Re loading. The metal loading was incorporated by using the pore volume impregnation method, employing aqueous solutions of cobalt (II) nitrate, ammonium molibdate and rhenium (VII) oxide. The catalysts were sulfided with dimethyl disulphide at 250 �C for 10 h and finally tested in the HDS reaction of thiophene and benzothiophene in different temperature and pressure conditions. The catalysts were characterized by determining the adsorption isotherms, the pore size distribution and the acid strengt, FTIR, XRD and S EM. T he catalyst supported on g - Al2O3 displayed higher activity than catalyst supported on g-Al2O3-HMS. The results suggest that activity is favoured by the suitable textural and acidic properties of the support.

The Effect of γ-Al2O3, TiO2 and ZrO2 Supports on Hydrodesulfurization Activity of Transition-Metal Sulfides

2008 ◽  
Vol 73 (8-9) ◽  
pp. 945-955 ◽  
Author(s):  
Luděk Kaluža ◽  
Miroslav Zdražil
Keyword(s):  
Transition Metal ◽  
Aqueous Solutions ◽  
Model Reaction ◽  
Metal Sulfides ◽  
Vacuum Impregnation ◽  
Transition Metal Sulfides ◽  
Highly Active ◽  
System A ◽  
Benzothiophene Hydrodesulfurization ◽  
Hydrodesulfurization Activity

The transition metals V, Cr, Mn, Fe, Co, Ni, Mo, Ru, Rh, Pd, W, Re, Os, Ir and Pt were deposited from aqueous solutions of their salts onto conventional γ-Al2O3 and unconventional TiO2 and ZrO2 supports by vacuum impregnation and characterized in their sulfided form by a model reaction of benzothiophene hydrodesulfurization. It was found that the TiO2 and ZrO2 supports influenced predominantly positively the resulting activity of relatively low-active metals (V, Cr, Mn, Fe, Co, Ni, Mo, Ru, W and Os), whereas the highly active metals (Rh, Pd, Ir, Pt and Re) were influenced slightly negatively or not at all by those supports compared with the γ-Al2O3-supported system. A significant effect of the supports on the hydrodesulfurization-activity ranking of the transition-metal sulfides studied was ascertained.

The relationship between geotechnical index properties and the pore-size distribution of compacted clayey silts

2015 ◽  
Vol 22 (6) ◽  
Author(s):  
Nazile Ural
Keyword(s):  
Specific Surface ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Correlation Coefficients ◽  
Liquid Limit ◽  
Index Properties

AbstractIn this study, the relationships between geotechnical index properties and the pore-size distribution of compacted natural silt and artificial soil mixtures, namely, silt with two different clays and three different clay percentages (10%, 20%, and 40%), were examined and compared. Atterberg’s limit tests, standard compaction tests, mercury intrusion porosimetry, X-ray diffraction, scanning electron microscopy (SEM) analysis, and Brunauer-Emmett-Teller specific surface analysis were conducted. The results show that the liquid limit, the cumulative pore volume, and specific surface area of artificially mixed soils increase with an increase in the percentage of clay. The cumulative pore volume and specific surface area with geotechnical index properties were compared. High correlation coefficients were observed between the specific areas and both the liquid limit and the plasticity index, as well as between the cumulative pore volume and both the clay percentage and the

Dehydrogenation of Propane to Propene over Mesoporous ZrO2-Supported VCrO Catalysts

2014 ◽  
Vol 1008-1009 ◽  
pp. 290-294
Author(s):  
Bao Agula ◽  
Si Qin Dalai ◽  
Yue Chao Wu
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Mesoporous Structure ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Size Distributions ◽  
Tem Analysis ◽  
Surfactant Assisted ◽  
Uniform Pore Size

Mesoporous ZrO2with narrow mesopore size distributions has been prepared by the surfactant-assisted method of nanoparticle assembly. A series of VCrO/ZrO2catalysts with different V/Cr molar ratio (0.3, 0.6, 1.0, 1.3 and 1.6) were prepared by the wetness impregnation method and characterized by XRD, N2adsorption and TEM techniques. N2adsorption and TEM analysis revealed that the surfactant-assisted method prepared VCrO/ZrO2catalysts have wormhole-like mesoporous structure with uniform pore size distribution. VCrO/ZrO2catalysts have been applied for direct dehydrogenation of propane to propene. The optimistic catalyst was V/Cr-0.6 with highest yield of 41.7% the corresponding conversion of propane was 44.1% and selectivity to propene was 94.5% at 550 °C.

Property of Cu2O-CuO/ZSM-5 nanocomposite and degradation process of azo dye AO7 without sacrificial agent (H2O2)

2016 ◽  
Vol 73 (11) ◽  
pp. 2747-2753 ◽  
Author(s):  
Wusong Kong ◽  
Hongxia Qu ◽  
Peng Chen ◽  
Weihua Ma ◽  
Huifang Xie
Keyword(s):  
Catalytic Activity ◽  
Aqueous Solutions ◽  
Photoelectron Spectroscopy ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Surface Element ◽  
Impregnation Method ◽  
X Ray ◽  
Initial Ph ◽  
Sacrificial Agent

In this study, Cu2O-CuO/ZSM-5 nanocomposite was synthesized by the impregnation method, and its catalytic performance for the destruction of AO7 in aqueous solutions was investigated. The morphology, structure and surface element valence state of Cu2O-CuO/ZSM-5 were characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The operating conditions on the degradation of AO7 by Cu2O-CuO/ZSM-5, such as initial pH values, concentration of AO7 and catalyst dosage were investigated and optimized. The results showed that the sample had good catalytic activity for destruction of AO7 in the absence of a sacrificial agent (e.g. H2O2): it could degrade 91% AO7 in 140 min at 25 °C and was not restricted by the initial pH of the AO7 aqueous solutions. Cu2O-CuO/ZSM-5 exhibited stable catalytic activity with little loss after three successive runs. The total organic carbon and chemical oxygen demand removal efficiencies increased rapidly to 69.36% and 67.3% after 120 min of treatment by Cu2O-CuO/ZSM-5, respectively.

scholarly journals Zeolites as alcohol adsorbents from aqueous solutions

2006 ◽  
pp. 83-87 ◽  
Author(s):  
Blagica Cekova ◽  
Dragi Kocev ◽  
Elena Kolcakovska ◽  
Daniela Stojanova
Keyword(s):  
Heat Treatment ◽  
Aqueous Solutions ◽  
Pore Volume ◽  
Industrial Wastewater ◽  
Organic Molecules ◽  
Adsorption Process ◽  
Aqueous Acetone ◽  
Heats Of Adsorption ◽  
Series Of Experiments ◽  
Low Costs

The potential usage of zeolites as adsorbents for the removal of organic molecules from water was investigated in a series of experiments with aqueous solutions of lower alcohols. This could represent a simple solution to the problem of cleaning up industrial wastewater as well as recovering valuable chemicals at relatively low costs. Adsorption isotherms of the Langmuir type were applied, and calculations showed that the amount of propanol adsorbed on silicalite corresponded to approximately 70% of the pore volume. The adsorption process is simple, and recovery of the more concentrated products is easily done by heat treatment and/or at lowered pressures. Adsorption experiments with aqueous acetone showed that silicalite had approximately the same adsorption capacity for acetone as for n-propanol. Heats of adsorption were determined calorimetrically.

scholarly journals Friedel-Crafts Acylation of Furan: Development of A Green Process Using Chromium-exchanged Dodecatungstophosphoric Acid: Effect of Support, Mechanism and Kinetic Modelling

2021 ◽  
Author(s):  
Deepak S. Desai ◽  
Ganapati D. Yadav
Keyword(s):  
Acetic Anhydride ◽  
Kinetic Modelling ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Support Mechanism ◽  
Full Characterization ◽  
Prior Art ◽  
Acid Effect ◽  
Ft Ir ◽  
Effect Of Support

Abstract The Friedel-Crafts acylation of furan with acetic anhydride to produce 2-acyl furan is industrially important. With an aim of replacing the highly polluting process, it this study, supported but modified heteropoly acids were used. Metal exchanged dodecatungstophosphoric acid (DTP) was loaded on three different supports and its effect on acylation was evaluated. Thus, chromium exchanged DTP was supported on K-10, SiO2, and ZrO2 using the incipient wetness impregnation method. 20% w/w Cr0.66-DTP/K-10 having the best activity for the acylation of furan with acetic anhydride was chosen for full characterization and reaction kinetics. Under optimized condition, the catalyst to furan ratio was 9.6%, significantly less as per prior art, which gave 88% conversion with 100% selectivity. The prepared catalysts were characterized by sophisticated techniques, namely, XRD, FT-IR, SEM, NH3-TPD, TGA, and BET. The Eley-Rideal mechanism was found to fit the kinetic data. The activation energy was found to be 18.03 kcal/mol. The reaction is green and clean as no chlorinated chemicals, reagents, and catalysts were used.

Equilibrium moisture content in wet pressing of paper

TAPPI Journal ◽  
2020 ◽  
Vol 19 (7) ◽  
pp. 330-340
Author(s):  
RICHARD KEREKES ◽  
DAVID MCDONALD
Keyword(s):  
Energy Expenditure ◽  
Moisture Content ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Pore Volume ◽  
Limiting Factor ◽  
High Solids ◽  
Solute Exclusion ◽  
Chemical Pulping ◽  
Pulp Strength

Equilibrium moisture is a limiting factor in achieving high solids in the later stages of pressing or pressing low basis weight grades. We have developed a model that relates equilibrium moisture directly to the pore size distribution of fibers as measured by the solute exclusion technique. The model shows that chemical pulping and refining increase equilibrium moisture by increasing pore volume at given pore sizes in fibers, which leads to lower pressed solids and greater energy expenditure in the dryer section. Means to increase equilibrium moisture without compromising pulp strength are briefly discussed.

scholarly journals Synthesis of shaped Pt nanoparticles using common anions or small molecules as shape-directing agents: observation of a strong halide or pseudo-halide effect

2015 ◽  
Vol 3 (5) ◽  
pp. 2012-2018 ◽  
Author(s):  
Jason A. Michel ◽  
William H. Morris III ◽  
Charles M. Lukehart
Keyword(s):  
Aqueous Solutions ◽  
Small Molecules ◽  
Pt Nanoparticles ◽  
Shape Selectivity ◽  
Colloidal Nanocrystals ◽  
Selection Of

Shape selectivity between cubic and tetrahedral Pt colloidal nanocrystals is achieved simply by selection of [Pt(OH)6]2− or [PtI6]2−, respectively, as the Pt precursor in basic aqueous solutions.

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