Coupled transport of cyanide ions through liquid membranes

2000 ◽  
Vol 41 (10-11) ◽  
pp. 125-133 ◽  
Author(s):  
C. Aydiner ◽  
M. Kobya ◽  
I. Koyuncu
Keyword(s):  
Liquid Membrane ◽  
Second Step ◽  
Liquid Membranes ◽  
Coupled Transport ◽  
First Order ◽  
Linear Relationships ◽  
Reversible Chemical Reaction ◽  
Different Temperatures ◽  
Kinetics Of ◽  
Tetraoctylammonium Chloride

In this study, the transport kinetics of coupled transport of cyanide ions through liquid membrane (trichloromethane) containing tetraoctylammonium chloride as a carrier was examined at different temperatures. The kinetics of cyanide transport could be analyzed in the formalism of two consecutive irreversible first order reactions. The influence of the temperature on the kinetic parameters (k1d, k2m, k2a, Rmmax, tmax, Jdmax, Jamax) has been established. For maximum membrane entrance and exit fluxes, Jdmax and Jamax, the activation energies were found from the slopes of the two linear relationships: 9.02 kcal/mol and 11.20 kcal/mol, respectively. The values of the found activation energy indicate that in the first step the transport process of cyanide ions through liquid membrane is difussional controlled, whereas in the second step it is most probably controlled by species diffusion and the rate of the reversible chemical reaction.

Effect of kinetic synergist on transport of copper(II) through a liquid membrane containing P507 in kerosene

2001 ◽  
Vol 79 (8) ◽  
pp. 1213-1219 ◽  
Author(s):  
Dingsheng He ◽  
Ming Ma ◽  
Hui Wang ◽  
Pandeng Zhou
Keyword(s):  
Activation Energy ◽  
Liquid Membrane ◽  
Copper Ions ◽  
Bulk Liquid ◽  
Liquid Membranes ◽  
Bulk Liquid Membrane ◽  
First Order ◽  
Pseudo First Order ◽  
Feed Phase ◽  
Kinetics Of

A new kinetic synergism system for copper(II) transport through a bulk liquid membrane containing mono(2-ethyhexyl)-2-ethyhexyl phosphate and Manoxol OT (OT) was examined. The influence of stripping agent, anion, pH in feed phase, and carrier concentration were investigated. The kinetics of Cu(II) transport could be analyzed in the formalism of two consecutive irreversible first-order reactions, considering both extraction and stripping. The pseudo-first-order apparent rate constants of interfacial reactions in membrane transport are determined by altering the temperature. The activation energy values are 38.1 kJ mol–1 for extraction and 32.8 kJ mol–1 for stripping. The experiments demonstrated that Manoxol OT is a good kinetic synergist for Cu(II) transport through liquid membranes in this study. The kinetic synergism of OT for extraction of Cu2+ ions is analyzed.Key words: copper ions, kinetic synergist, liquid membrane.

scholarly journals A Logistic Approach for Kinetics of Isothermal Pyrolysis of Cellulose

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 551
Author(s):  
Jorge López-Beceiro ◽  
Ana María Díaz-Díaz ◽  
Ana Álvarez-García ◽  
Javier Tarrío-Saavedra ◽  
Salvador Naya ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Time Derivative ◽  
Inert Atmosphere ◽  
Second Step ◽  
Rate Parameter ◽  
Thermogravimetric Data ◽  
Different Temperatures ◽  
Parameter Values ◽  
Kinetics Of ◽  
Logistic Functions

A kinetic model is proposed to fit isothermal thermogravimetric data obtained from cellulose in an inert atmosphere at different temperatures. The method used here to evaluate the model involves two steps: (1) fitting of single time-derivative thermogravimetric curves (DTG) obtained at different temperatures versus time, and (2) fitting of the rate parameter values obtained at different temperatures versus temperature. The first step makes use of derivative of logistic functions. For the second step, the dependence of the rate factor on temperature is evaluated. That separation of the curve fitting from the analysis of the rate factor resulted to be very flexible since it proved to work for previous crystallization studies and now for thermal degradation of cellulose.

scholarly journals Reactivity of Phenol and Aniline towards Quinolinium Chloro Chromate: A Comparative Oxidation Kinetic Study

2015 ◽  
Vol 59 ◽  
pp. 81-92
Author(s):  
Seplapatty Kalimuthu Periyasamy ◽  
H. Satham Hussain ◽  
R. Manikandan
Keyword(s):  
Oxidation Kinetic ◽  
Activation Parameters ◽  
Dipole Interaction ◽  
Reaction Rates ◽  
Hydrogen Ion ◽  
Aqueous Acetic Acid ◽  
Acetic Acid Medium ◽  
First Order ◽  
Different Temperatures ◽  
Kinetics Of

The kinetics of Oxidation of Phenol and aniline by quinolinium Chlorochromate (QCC) in aqueous acetic acid medium leads to the formation of quinone and azobenzene respectively. The reactions are first order with respect to both Phenol and aniline. The reaction is first order with respect to quinolinium chlorochromate (QCC) and is catalyzed by hydrogen ion. The hydrogen-ion dependence has the form: kobs = a+b [H+]. The rate of oxidation decreases with increasing dielectric constant of solvent, indicating the presence of an ion-dipole interaction. The reaction does not induced the polymerization of acrylonitrile. The retardation of the rate by the addition of Mn2+ ions confirms that a two electron transfer process is involved in the reaction. The reaction rates have been determined at different temperatures and the activation parameters have been calculated. From the above observations kinetic results a probable mechanism have been proposed.

Thermal Inactivation Kinetics of Sporolactobacillus nakayamae Spores, a Spoilage Bacterium Isolated from a Model Mashed Potato–Scallion Mixture

2016 ◽  
Vol 79 (9) ◽  
pp. 1482-1489
Author(s):  
HAYRIYE BOZKURT ◽  
JAIRUS R. D. DAVID ◽  
RYAN J. TALLEY ◽  
D. SCOTT LINEBACK ◽  
P. MICHAEL DAVIDSON
Keyword(s):  
Heat Resistance ◽  
Thermal Inactivation ◽  
Weibull Model ◽  
Inactivation Kinetics ◽  
Order Model ◽  
First Order ◽  
Different Temperatures ◽  
Spoilage Bacterium ◽  
D Values ◽  
Kinetics Of

ABSTRACT Sporolactobacillus species have been occasionally isolated from spoiled foods and environmental sources. Thus, food processors should be aware of their potential presence and characteristics. In this study, the heat resistance and influence of the growth and recovery media on apparent heat resistance of Sporolactobacillus nakayamae spores were studied and described mathematically. For each medium, survivor curves and thermal death curves were generated for different treatment times (0 to 25 min) at different temperatures (70, 75, and 80°C) and Weibull and first-order models were compared. Thermal inactivation data for S. nakayamae spores varied widely depending on the media formulations used, with glucose yeast peptone consistently yielding the highest D-values for the three temperatures tested. For this same medium, the D-values ranged from 25.24 ± 1.57 to 3.45 ± 0.27 min for the first-order model and from 24.18 ± 0.62 to 3.50 ± 0.24 min for the Weibull model at 70 and 80°C, respectively. The z-values determined for S. nakayamae spores were 11.91 ± 0.29°C for the Weibull model and 11.58 ± 0.43°C for the first-order model. The calculated activation energy was 200.5 ± 7.3 kJ/mol for the first-order model and 192.8 ± 22.1 kJ/mol for the Weibull model. The Weibull model consistently produced the best fit for all the survival curves. This study provides novel and precise information on thermal inactivation kinetics of S. nakayamae spores that will enable reliable thermal process calculations for eliminating this spoilage bacterium.

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

2019 ◽  
Vol 44 (4) ◽  
pp. 307-315 ◽  
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.

Kinetics of the Substitution of Norbornadiene in Tetracarbonyl(norbomadiene)molybdenum(0) by 2,2'-Bipyridine

2001 ◽  
Vol 56 (3) ◽  
pp. 281-286 ◽  
Author(s):  
Ceyhan Kayran ◽  
Eser Okan
Keyword(s):  
Reaction Rate ◽  
Activation Parameters ◽  
Bipy Ligand ◽  
First Order ◽  
Rate Determining Step ◽  
Vis Spectroscopy ◽  
Different Temperatures ◽  
Ft Ir ◽  
Thermal Substitution ◽  
Kinetics Of

Abstract The kinetics of the thermal substitution of norbornadiene (nbd) by 2,2'-bipyridine (2,2'-bipy) in (CO)4Mo(C7H9) was studied by quantitative FT-IR and UV-VIS spectroscopy. The reaction rate exhibits first-order dependence on the concentration of the starting complex, and the observed rate constant depends on the concentration of both leaving nbd and entering 2,2'-bipy ligand. The mechanism was found to be consistent with the previously proposed one, where the rate determining step is the cleavage of one of the two Mo-olefin bonds. The reaction was performed at four different temperatures (35 -50 °C) and the evaluation of the kinetic data gives the activation parameters which now support states.

scholarly journals Thermodynamics and kinetics of thermal deactivation of catalase Aspergillus niger

2020 ◽  
Vol 22 (2) ◽  
pp. 67-72
Author(s):  
Justyna Miłek
Keyword(s):  
Aspergillus Niger ◽  
Life Time ◽  
Economic Feasibility ◽  
Thermal Deactivation ◽  
Order Model ◽  
First Order ◽  
Thermodynamics And Kinetics ◽  
Different Temperatures ◽  
Kinetics Of ◽  
Thermal Stability Of

AbstractThe thermal stability of enzyme-based biosensors is crucial in economic feasibility. In this study, thermal deactivation profiles of catalase Aspergillus niger were obtained at different temperatures in the range of 35°C to 70°C. It has been shown that the thermal deactivation of catalase Aspergillus niger follows the first-order model. The half-life time t1/2 of catalase Aspergillus niger at pH 7.0 and the temperature of 35°C and 70°C were 197 h and 1.3 h respectively. Additionally, t1/2 of catalase Aspergillus niger at the temperature of 5°C was calculated 58 months. Thermodynamic parameters the change in enthalpy ΔH*, the change in entropy ΔS* and the change Gibbs free energy ΔG* for the deactivation of catalase at different temperatures in the range of 35°C to 70°C were estimated. Catalase Aspergillus niger is predisposed to be used in biosensors by thermodynamics parameters obtained.

The Kinetics of Quinoline Hydrodenitrogenation through Reaction Intermediate Products

1975 ◽  
Vol 53 (17) ◽  
pp. 2575-2579 ◽  
Author(s):  
Ahmed Kadry Aboul-Gheit
Keyword(s):  
Order Reaction ◽  
Second Step ◽  
Activation Entropy ◽  
Ammonia Production ◽  
Alumina Catalyst ◽  
High Activation ◽  
Reaction Sequence ◽  
First Order ◽  
The Third ◽  
Kinetics Of

Under petroleum hydrotreating conditions and in the presence of a Co–M–alumina catalyst, quinoline is hydrodenitrogenated through a consecutive first order reaction involving a hydrogénation step followed by two hydrocracking steps. The first step is too fast to measure whereas the second step is the slowest. The ratio of the rate constants of the second to the third step ranges between 0.33 and 0.62 at reaction temperatures between 350 and 400 °C. The second step can be considered responsible for the relatively high activation energy and enthalpy values obtained for the overall reaction. The activation entropy obtained for the overall reaction is −38.2 e.u. mol−1, while the second and the third steps have values of −43.9 and −58.0 e.u. mol−1, respectively. These values indicate the progressive complexity of the steps involved in the reaction sequence as it proceeds towards ammonia production.

Kinetics and mechanism of aminolysis of (Z)-4-arylidene-2-phenyl-5(4H)oxazolones

1992 ◽  
Vol 70 (10) ◽  
pp. 2515-2519 ◽  
Author(s):  
Sharifa S. Alkaabi ◽  
Ahmad S. Shawali
Keyword(s):  
Rate Constants ◽  
Activation Parameters ◽  
Order Conditions ◽  
Kinetics And Mechanism ◽  
Hammett Equation ◽  
Third Order ◽  
First Order ◽  
Different Temperatures ◽  
Pseudo First Order ◽  
Kinetics Of

The kinetics of the reactions of a series of (Z)-4-arylidene-2-phenyl-5(4H)oxazolones 1 with n-butylamine and piperidine were studied spectrophotometrically in dioxane, ethanol, and cyclohexane under pseudo-first-order conditions and at different temperatures. The relation k1(obs) = k2[amine] + k3[amine]2 was found applicable for all reactions studied in either dioxane or ethanol. However, in cyclohexane the n-butylaminolysis of 1 followed only third-order kinetics k1(obs) = k3[n-BuNH2]2. The kinetics of the reaction of 1 with n-butylamine in the presence of catalytic amounts of triethylamine in dioxane followed the equation: k1(obs)k2 = [n-BuNH2] + k3[n-BuNH2]2[Formula: see text] [Et3N]. The rate constants k2 and k3 correlated well with the Hammett equation and the corresponding activation parameters were determined. The results were interpreted in terms of a mechanism involving solvent- and amine-catalyzed processes.

scholarly journals Thermodynamics of copper desorption from soils as affected by citrate and succinate

2008 ◽  
Vol 2 (No. 4) ◽  
pp. 135-140 ◽  
Author(s):  
E.A. Elkhatib ◽  
A.M. Mahdy ◽  
N.H. Barakat
Keyword(s):  
Contaminated Soils ◽  
Reaction Rate Constant ◽  
Organic Ligands ◽  
Order Kinetic ◽  
First Order ◽  
Dissolved Organics ◽  
Different Temperatures ◽  
Energy Consuming ◽  
Delta G ◽  
Kinetics Of

Desorption of Cu and low molecular weight dissolved organics are the primary factors that impact fate and transport of Cu in soils. To improve predictions of the toxicity and threat from Cu contaminated soil, it is critical that time-dependent desorption behaviour be understood. In this paper, the effect of organic ligands citrate and succinate on the kinetics of Cu desorption from contaminated soils varying widely in soil characteristics was investigated at three different temperatures. The results showed that the first order equation adequately described the kinetics of Cu desorption from clay and sandy soils under isothermal conditions. The reaction rate constant (k<sub>d</sub>) values of the first order kinetic equation for Cu desorption increased consistently with temperature, indicating faster release of Cu at higher temperatures. The Cu desorption rate from the studied soils at all three temperatures was as follows: citric &gt; succinic. The E<sub>a</sub>values indicates that Cu desorption from the studied soils in the presence of two organic ligands is a diffusion controlled reaction. The negative values of &Delta;H* suggest that the desorption reactions are not energy consuming process. The higher negative values of (&Delta;H*) for Cu desorption from the studied soils in the presence of succinic ligand indicate that the heat energy required to overcome the Cu desorption barrier was greater than that for Cu desorption in the presence of citric ligand. Computation of the free energy of activation (&Delta;G*) yielded values ranging for 87 to 87.9 kJ/mol. The largest value represents &Delta;G* for Cu desorption for clay soil in the presence of succinic acid while the lowest value represents &Delta;G* for Cu desorption for sandy soil in the presence of citric acid. The information in this study is quite necessary to construct full functioning models that will help scientists to better understand mobility and bioavailability of metals in soils.

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