Akinetic study of the depyritization of oil shale HCl-kerogen concentrate by Thiobacillus ferrooxidans at different temperatures

The results of kinetic studies of bacterial depyritization of HCl-kerogen concentrate of Aleksinac (Serbia) oil shale by the chemolithoautotrophic thionic bacteria Thiobacillus ferrooxidans under discontinuous laboratory conditions at various temperatures (0, 20, 28 and 37 ?C) at a pH of ca. 1.5 are presented in this paper. Low pH prevents the occurrence of the precipitation of iron(III)-ion hydrolysis products on the substrate particles and thereby reduces the process efficiency. Bacterial depyritization is developed as per kinetics of the first order. The activation energy which points to a successive mechanism of pyrite biooxidation, was computed from the Arrhenius plot. The biochemical kinetics indicators point to a high affinity of the bacteria toward pyrite but small values of Vmax, which are probably the result of decelerated metabolic processes due to the low pH value of the environment resp. the large difference of thepHbetween the external medium and the cell interior.

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Comparative Labelling and Biokinetic Studies of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn)

Nuklearmedizin ◽

10.1055/s-0037-1620603 ◽

1977 ◽

Vol 16 (01) ◽

pp. 30-35 ◽

Cited By ~ 1

Author(s):

N. Agha ◽

R. B. R. Persson

Keyword(s):

Complex Formation ◽

Significant Influence ◽

Room Temperature ◽

Ph Value ◽

Maximum Activity ◽

Reduction Step ◽

Labelling Yield ◽

Different Temperatures ◽

Kinetics Of

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).

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Reactivity and kinetic studies of benzofuran hydrodeoxygenation over a Ni2P-O/MCM-41 catalyst

Progress in Reaction Kinetics and Mechanism ◽

10.1177/1468678319825909 ◽

2019 ◽

Vol 44 (4) ◽

pp. 307-315 ◽

Cited By ~ 1

Author(s):

Xueya Dai ◽

Hua Song ◽

Hualin Song ◽

Jing Gong ◽

Feng Li ◽

...

Keyword(s):

Kinetic Studies ◽

Time Analysis ◽

Liquid Ratio ◽

Order Model ◽

Free Products ◽

First Order ◽

Reaction Rate Constants ◽

Different Temperatures ◽

Kinetics Of ◽

Mcm 41

A nickel phosphide hydrodeoxygenation catalyst (Ni2P-O/MCM-41) was prepared using a new synthetic method. The as-prepared catalyst was evaluated in the hydrodeoxygenation of benzofuran, and the effects of reaction temperature, pressure, and the H2/liquid ratio were investigated. A pseudo first-order model was employed to describe the reaction kinetics of benzofuran hydrodeoxygenation over the Ni2P-O/MCM-41 catalyst. The reaction rate constants ( k1– k5) at different temperatures were determined according to this model. At 533 K, the conversion of 2-ethylphenol in to ethylbenzene began to increase dramatically, and the yield of O-free product, ethylcyclohexane, started to increase rapidly. At 573 K, 3.0 MPa, and a H2/liquid ratio of 500 (V/V), the conversion of benzofuran over Ni2P-O/MCM-41 reached 93%, and the combined yield of O-free products was 91%. Contact time analysis indicated that demethylation was not favored over the Ni2P-O/MCM-41 catalyst.

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Application of the Shrinking-Core Models for Determination of Dissolution Kinetics of Mn and Zn from Spent Zinc–Carbon Battery Powder in Organic Acid Solution

Acta Chemica Iasi ◽

10.2478/achi-2019-0008 ◽

2019 ◽

Vol 27 (1) ◽

pp. 99-109 ◽

Cited By ~ 1

Author(s):

Tevfik Agacayak ◽

Hasan Ali Taner

Keyword(s):

Acetic Acid ◽

Acid Solution ◽

Acetic Acid Solution ◽

Dissolution Kinetics ◽

Kinetic Studies ◽

Product Layer ◽

Different Temperatures ◽

Shrinking Core ◽

Kinetics Of Dissolution ◽

Kinetics Of

Abstract In this study, dissolution kinetics of manganese and zinc from spent zinc–carbon batteries in acetic acid solution was investigated. To determine the kinetics of dissolution of manganese and zinc, shrinking core model was applied to dissolution recoveries obtained at different temperatures. As a result of kinetic studies, it was determined that manganese and zinc were dissolved in acetic acid solution by diffusion from product layer and then activation energies (Ea) were calculated.

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Aquation reaction of iminodiacetate complex of oxidovanadium(IV) with 2,2’-bipyridine induced by Fe(III) ions: Kinetic studies

Progress in Reaction Kinetics and Mechanism ◽

10.1177/1468678319850496 ◽

2019 ◽

Vol 44 (4) ◽

pp. 300-306

Author(s):

Joanna Drzeżdżon ◽

Agnieszka Piotrowska-Kirschling ◽

Lech Chmurzyński ◽

Dagmara Jacewicz

Keyword(s):

Aqueous Solutions ◽

Computer Program ◽

Rate Constants ◽

Reaction Rate ◽

Kinetic Studies ◽

Reaction Rate Constants ◽

Different Temperatures ◽

Kinetics Of

The kinetics of the aquation reaction of the [VO(ida)(bipy)]·2H2O (VO(ida)(bipy)) complex (where ida = iminodiacetate anion and bipy = 2,2’-bipyridine) promoted by [Fe(H2O)6]3+ ions were investigated in aqueous solutions. Spectrophotometric studies were carried out at different temperatures in the range of 293.15–313.15 K. The concentration of the [Fe(H2O)6]3+ (Fe3+) ions was kept within the range of 2 × 10–4 to 8 × 10–4 mol L–1, and the concentration of VO(ida)(bipy) was 1 × 10–3 mol L–1. The values of the observable reaction rate constants were calculated based on the Glint computer program. Furthermore, the mechanism for the aquation of VO(ida)(bipy), induced by Fe(III) ions, has been proposed.

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Kinetic Treatment of the Reaction of Fructose and N-Bromosuccinimide in Cationic/Anionic/Nonionic Micelles

Journal of Soft Matter ◽

10.1155/2014/791563 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10

Author(s):

Minu Singh

Keyword(s):

Fractional Order ◽

Activation Parameters ◽

Kinetic Studies ◽

Stoichiometric Ratio ◽

Product Analysis ◽

First Order ◽

Order Dependence ◽

Different Temperatures ◽

Reaction Stoichiometry ◽

Kinetics Of

The kinetics of oxidation of fructose by N-bromosuccinimide in acidic medium in the absence and presence of cationic, anionic, and nonionic surfactants has been measured iodometrically under pseudo-first-order condition. The oxidation kinetics of fructose by N-bromosuccinimide shows a first-order dependence on N-bromosuccinimide, fractional order dependence on fructose, and negative fractional order dependence on sulfuric acid. The kinetics is treated using Berezin’s micellar model that was previously used for the catalysis and inhibition of the reaction. The determined stoichiometric ratio was 1 : 1 (fructose : N-bromosuccinimide). The variation of Hg(OAC)2 and succinimide (reaction product) has insignificant effect on reaction rate. Effects of surfactants, added acrylonitrile, added salts, and solvent composition variation have been studied. Activation parameters for the reaction have been evaluated from Arrhenius plot by studying the reaction at different temperatures. The rate law has been derived on the basis of obtained data. A plausible mechanism has been proposed from the results of kinetic studies, reaction stoichiometry, and product analysis.

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Kinetic studies of the reactions between isocyanates and carboxylic acids

High Performance Polymers ◽

10.1088/0954-0083/6/3/006 ◽

1994 ◽

Vol 6 (3) ◽

pp. 235-239 ◽

Cited By ~ 6

Author(s):

Hong Xiao ◽

Han X Xiao ◽

Kurt C Frisch ◽

Nelson Malwitz

Keyword(s):

Carboxylic Acids ◽

Reaction Kinetic ◽

Arrhenius Plot ◽

Kinetic Studies ◽

Isobutyric Acid ◽

Phenyl Isocyanate ◽

Order Reaction ◽

Second Order Reaction ◽

Different Temperatures ◽

Kinetics Of

Reaction kinetic studies between isocyanates and carboxylic acids were undertaken to evaluate the kinetic parameters. Various isocyanates (phenyl isocyanate, cyclohexyl isocyanate) and carboxylic acids (acetic acid, n-butyric acid, isobutyric acid, dimethylbutyric acid and benzoic acid) were used to study the kinetics of the reactions at different temperatures and in different solvents. It was found that these reactions followed the rate law of second-order reaction. From the Arrhenius plot, the activation energies of these reactions were computed.

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Thermodynamic and detailed kinetic study of the formation of orthophthalaldehyde-agmatine complex by fluorescence intensities

Journal of Analytical Science & Technology ◽

10.1186/s40543-020-00238-2 ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Khémesse Kital ◽

Moumouny Traoré ◽

Diégane Sarr ◽

Moussa Mbaye ◽

Mame Diabou Gaye Seye ◽

...

Keyword(s):

Complex Formation ◽

Thermodynamic Parameters ◽

Initial Rate ◽

Reaction Medium ◽

Standard Entropy ◽

Step Size ◽

Formation Reaction ◽

Different Temperatures ◽

Kinetics Of ◽

Complex Formation Process

Abstract The aim of this work is to determine the thermodynamic parameters and the kinetics of complex formation between orthophthalaldehyde (OPA) and agmatine (AGM) in an alkaline medium (pH 13). Firstly, the association constant (Ka) between orthophthalaldehyde and agmatine was determined at different temperatures (between 298 K and 338 K) with a step size of 10 K. Secondly, the thermodynamic parameters such as standard enthalpy (ΔH°), standard entropy (ΔS°),and Gibbs energy (∆G) were calculated, where a positive value of ΔH° (+45.50 kJ/mol) was found, which shows that the reaction is endothermic. In addition, the low value of ΔS°(+0.24 kJ/mol) indicates a slight increase in the disorder in the reaction medium. Furthermore, the negative values of ΔG between −35.62 kJ/mol and −26.02 kJ/mol show that the complex formation process is spontaneous. Finally, the parameters of the kinetics of the reaction between OPA and AGM were determined as follows: when the initial concentration of AGM (5 × 10−6 M) is equal to that of the OPA, the results show that the reaction follows an overall 1.5 order kinetics with an initial rate of 5.1 × 10−7Mmin−1 and a half-life of 8.12 min. The partial order found in relation to the AGM is 0.8. This work shows that the excess of OPA accelerates the formation reaction of the complex.

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Oxidation Kinetics of Oil Shale Semicokes: Reactivity as a Function of Pyrolysis Temperature and Shale Origin

Energy & Fuels ◽

10.1021/ef3015052 ◽

2013 ◽

Vol 27 (2) ◽

pp. 666-672 ◽

Cited By ~ 19

Author(s):

Jillian L. Goldfarb ◽

Anthony D’Amico ◽

Christopher Culin ◽

Eric M. Suuberg ◽

Indrek Külaots

Keyword(s):

Oxidation Kinetics ◽

Oil Shale ◽

Pyrolysis Temperature ◽

Kinetics Of

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Torrefaction Thermogravimetric Analysis and Kinetics of Sorghum Distilled Residue for Sustainable Fuel Production

Sustainability ◽

10.3390/su13084246 ◽

2021 ◽

Vol 13 (8) ◽

pp. 4246

Author(s):

Shih-Wei Yen ◽

Wei-Hsin Chen ◽

Jo-Shu Chang ◽

Chun-Fong Eng ◽

Salman Raza Naqvi ◽

...

Keyword(s):

Kinetic Model ◽

Pso Algorithm ◽

Nitrogen Atmosphere ◽

Computational Method ◽

Weight Changes ◽

Design And Optimization ◽

Thermogravimetric Analyzer ◽

Model Free ◽

Different Temperatures ◽

Kinetics Of

This study investigated the kinetics of isothermal torrefaction of sorghum distilled residue (SDR), the main byproduct of the sorghum liquor-making process. The samples chosen were torrefied isothermally at five different temperatures under a nitrogen atmosphere in a thermogravimetric analyzer. Afterward, two different kinetic methods, the traditional model-free approach, and a two-step parallel reaction (TPR) kinetic model, were used to obtain the torrefaction kinetics of SDR. With the acquired 92–97% fit quality, which is the degree of similarity between calculated and real torrefaction curves, the traditional method approached using the Arrhenius equation showed a poor ability on kinetics prediction, whereas the TPR kinetic model optimized by the particle swarm optimization (PSO) algorithm showed that all the fit qualities are as high as 99%. The results suggest that PSO can simulate the actual torrefaction kinetics more accurately than the traditional kinetics approach. Moreover, the PSO method can be further employed for simulating the weight changes of reaction intermediates throughout the process. This computational method could be used as a powerful tool for industrial design and optimization in the biochar manufacturing process.

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