Kinetics of dibenzothiophene hydrodesulfurization over MoS2 supported catalysts: modelization of the H2S partial pressure effect

1998 ◽  
Vol 170 (2) ◽  
pp. 195-206 ◽  
Author(s):  
E. Olguin Orozco ◽  
M. Vrinat
Keyword(s):  
Partial Pressure ◽  
Pressure Effect ◽  
Supported Catalysts ◽  
Kinetics Of

Effect of H2O Partial Pressure on Reduction Kinetics of Iron-Based Fischer-Tropsch Catalyst

2010 ◽  
Vol 31 (2) ◽  
pp. 205-212
Author(s):  
Hong WANG ◽  
Yong YANG ◽  
Baoshan WU ◽  
Jian XU ◽  
Hulin WANG ◽  
...  
Keyword(s):  
Partial Pressure ◽  
Reduction Kinetics ◽  
Fischer Tropsch ◽  
Iron Based ◽  
Kinetics Of

scholarly journals Leaching of Silver Contained in Mining Wastes Using the Thiosemicarbazide – Oxygen System

2018 ◽  
Author(s):  
Eleazar-Rodríguez Salinas ◽  
Juan Hernández-Ávila ◽  
Ma. Isabel Reyes-Valderrama ◽  
Eduardo Cerecedo-Sáenz ◽  
Demetrio Mendoza-Anaya ◽  
...  
Keyword(s):  
Partial Pressure ◽  
Effect Of Temperature ◽  
Mining Wastes ◽  
Leaching Rate ◽  
Partial Pressure Of Oxygen ◽  
Silver Recovery ◽  
Oxygen System ◽  
Stirring Rate ◽  
Kinetics Of ◽  
Representative Samples

The mining wastes generated during the last decades in the mining region of Pachuca-Real del Monte in Mexico, still contains silver values of interest. For this reason, the present work is a preliminary study of the leaching kinetics of silver contained in these residues, using as a leaching reagent the thiosemicarbazide-oxygen system, with the aim of proposing this leaching system as a less toxic alternative than cyaniding process. Previous the leaching process, representative samples were wholly characterized, finding 56 g of Ag and 0.6 g of Au per ton. For the kinetic study in the mentioned system, were evaluated the reagent concentration, temperature, partial pressure of oxygen, pH and stirring rate. According the experimental results found, it was observed that [CH5N3S] concentration showed a significant effect on the leaching rate, obtaining a reaction order of n = 0.93, in the range of 20 - 40 mol CH5N3S ⋅ m-3, getting so a silver recovery up to 76.9%. The effect of temperature gave an activation energy of Ea = 45.55 KJ mol-1, which was indicative of a chemical reaction control. Finally, partial pressure of oxygen has a notable effect on leaching rate, but pH and stirring rate have not apparent effect.

Salp metabolism: temperature and oxygen partial pressure effect on the physiology of Salpa fusiformis from the California Current

2019 ◽  
Vol 41 (3) ◽  
pp. 281-291
Author(s):  
Lloyd A Trueblood
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Carbon Cycling ◽  
Pressure Effect ◽  
California Current ◽  
Deep Ocean ◽  
Hypoxia Tolerance ◽  
Metabolic Rates ◽  
Physiological Processes ◽  
The Impact

Abstract Salps are pelagic tunicates that play an important role in carbon cycling by filter feeding and packaging waste into dense fecal pellets that sink rapidly to the deep ocean. There has been limited research on salp physiology and no studies that examine how changes in environmental factors such as temperature and dissolved oxygen impact basic physiological processes. Here I examine temperature and oxygen partial pressure effect on metabolism in blastozooids of Salpa fusiformis. Routine metabolic rates of 1.66 and 3.95 μmol O2 g−1 h−1 wet weight at 10°C and 17°C, respectively, resulted in a Q10 = 3.45. The observed decrease in metabolism associated with decreased temperature, as well as hypoxia tolerance, is explored in the context of observed vertical migrations into hypoxic waters in the California Current, and potential impacts on carbon output. Metabolic rates for S. fusiformis are compared to metabolic rates published for other species of salps and gelatinous zooplankton. Expansion of this work across a broader set of species is critical to quantify the impact climate change may have on salps and their role in marine carbon cycling.

Kinetics and mechanism of destruction of cobalt phthalocyanine derivatives in aqueous solutions

2000 ◽  
Vol 04 (07) ◽  
pp. 684-688 ◽  
Author(s):  
S. A. BORISENKOVA ◽  
E. P. DENISOVA ◽  
E. A. BATANOVA ◽  
E. G. GIRENKO ◽  
O. L. KALIYA ◽  
...  
Keyword(s):  
Kinetic Equation ◽  
Aqueous Solutions ◽  
Partial Pressure ◽  
Initial Solution ◽  
Cobalt Phthalocyanine ◽  
Oxidative Destruction ◽  
Partial Pressure Of Oxygen ◽  
Concentration Interval ◽  
Kinetics Of ◽  
Bleaching Rate

The kinetics of the oxidative destruction of cobalt phthalocyanine derivatives in aqueous solutions has been investigated in the concentration interval 10−4–10−5 M as a function of the concentration of alkali and the partial pressure of oxygen in the system. The kinetic equation for the initial solution bleaching rate is obtained. A mechanism of cobalt phthalocyanine destruction involving an intermediate Co (II) → Co (III) oxidation step is suggested.

KINETICS OF ELECTROCHEMICAL REACTIONS ON MODEL SUPPORTED CATALYSTS: READSORPTION AND MASS TRANSPORT

2008 ◽  
Vol 15 (06) ◽  
pp. 745-751
Author(s):  
VLADIMIR P. ZHDANOV ◽  
BENGT KASEMO
Keyword(s):  
Mass Transport ◽  
Supported Catalysts ◽  
Reaction Scheme ◽  
Electrochemical Reactions ◽  
Subsequent Reaction ◽  
Flow Cells ◽  
2D And 3D ◽  
Kinetics Of ◽  
And Diffusion

To bridge the structure gap, electrochemical reactions can be studied in flow cells with nm-sized catalyst particles deposited or fabricated on the cell walls. The understanding of the role of mass transport in such cells is now limited. To clarify the likely effects in this field, we analyze the simplest reaction scheme including intermediate desorption, readsorption, and subsequent reaction and show how the net rate of the formation of intermediate can be influenced by its diffusion in the liquid phase. With certain approximations, we derive analytical results describing reaction and diffusion near catalyst particles and in more remote regions in the simplest 1D case and more complex 2D and 3D situations.

Pressure Effect on the Kinetics of Reaction Between Solid NaCl and ZrCl4 or HfCl4 Vapors

1971 ◽  
Vol 49 (17) ◽  
pp. 2885-2890 ◽  
Author(s):  
P. Pint ◽  
S. N. Flengas
Keyword(s):  
Sodium Chloride ◽  
Single Crystals ◽  
Constant Temperature ◽  
Pressure Effect ◽  
Heterogeneous Reaction ◽  
Zirconium Tetrachloride ◽  
Hafnium Tetrachloride ◽  
Diffusion Controlled ◽  
Kinetics Of Reaction ◽  
Kinetics Of

The kinetics of reaction between single crystals of sodium chloride and zirconium tetrachloride and hafnium tetrachloride vapors, to form sodium hexachlorozirconate and sodium hexachlorohafnate, respectively, have been investigated as a function of the tetrachloride pressures at a constant temperature of 485 °C. The rate of formation of Na2ZrCl6 is kinetically more favorable. The heterogeneous reaction is diffusion controlled, with the rate of diffusion depending on the availability of Cl− vacancies.

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