The Kinetics of Manganese Sorption on Ukrainian Tuff and Basalt—Order and Diffusion Models Analysis

The study aimed to determine the nature of the kinetics of the manganese sorption process on Ukrainian tuff and basalt at different temperatures characteristic of the natural water environment. The scope of the research included manganese sorption kinetic test on natural mineral sorbents at temperatures of 10, 17.5 and 25 °C in slightly acidic conditions. Sorption (pseudo-first order, pseudo-second order and Elovich models) and diffusion kinetic models (liquid film diffusion and intraparticle diffusion) were used in the analysis of test results. The manganese sorption process on both tuff and basalt proceeded quickly. The dynamic equilibrium state of manganese sorption settled after 35 and 45 min on tuff and basalt respectively. Although the process took place in a slightly acidic environment and below pHPZC of the sorbents, possible electrostatic repulsion did not inhibit the removal of Mn. The Mn sorption on both materials followed the PSO kinetics model. Based on the diffusion kinetic models, it was determined that Mn sorption process on both materials was influenced by diffusion through the boundary layer and intraparticle diffusion. The differences in removal efficiency and rate of Mn sorption in the temperature range of 10–25 °C were not found.

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Biosorption and Diffusion Modeling of Pb(II) by Malt Bagasse

International Journal of Chemical Engineering ◽

10.1155/2016/4210561 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11 ◽

Cited By ~ 4

Author(s):

Klaiani B. Fontana ◽

Giane Gonçalves Lenzi ◽

Erica R. L. R. Watanabe ◽

Ervin Kaminski Lenzi ◽

Juliana A. M. T. Pietrobelli ◽

...

Keyword(s):

Sorption Process ◽

Isotherm Models ◽

Diffusion Modeling ◽

Biosorption Capacity ◽

Kinetic And Thermodynamic Parameters ◽

Pseudo Second Order ◽

Ph Optimization ◽

Kinetics Of ◽

And Diffusion

The removal of Pb(II) from water by biosorption processes onto malt bagasse was investigated and the kinetic and thermodynamic parameters were obtained; additionally a diffusion modeling was proposed. The characterization of malt bagasse was performed by FTIR and SEM/EDS. The experiments were conducted in batch system and an experimental design based response surface methodology was applied for agitation speed and pH optimization. The kinetics of biosorption followed pseudo-second-order model and the temperature of the process affected the biosorption capacity. Isotherm models of Langmuir, Freundlich, and Elovich were applied and the Langmuir model showed better fit and the estimated biosorption capacity was 29.1 mg g−1. The negative values obtained for ΔG° and positive values of ΔH° confirm, respectively, the spontaneous and endothermic nature of the process. The diffusion modeling was performed based on experiments in the absence of agitation to investigate the influence of the biosorbent on the sorption process of Pb(II) ions.

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Kinetics of removal of zinc ions from aqueous solutions by a modified acrylnitrile copolymer

Water Science & Technology ◽

10.2166/wst.1999.0406 ◽

1999 ◽

Vol 39 (8) ◽

pp. 139-146

Author(s):

R. Y. Stefanova

Keyword(s):

Aqueous Solutions ◽

Metal Ions ◽

Sorption Process ◽

Intraparticle Diffusion ◽

Zinc Ions ◽

Sorption System ◽

Modified Polymer ◽

Rate Limiting Step ◽

High Sorption ◽

Kinetics Of

The kinetics of removal of zinc ions from aqueous solutions by a modified acrylnitrile copolymer containing carboxyl and amino groups has been investigated. The dependence of the rate of removal on the intensity of stirring, the size of the sorbent's particles, the initial concentration of metal ions and the temperature of the solution have been established. Attempts have been made to identify the rate limiting step and to determine the batch kinetic parameters. The limiting conditions of the transition from external to intraparticle diffusion step of mass transfer in a sorption system have been determined. The coefficients of intraparticle diffusion and the energy of activation of the sorption process have been established. The data obtained in this work show that the modified polymer with a high sorption capacity and very good kinetic characteristics can be successfully used for removal of heavy metal ions from water solutions and industrial wastewaters.

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Nitridation Isothermal Kinetics of In Situ β-Sialon Bonded Al2O3-C Refractories

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.697.572 ◽

2016 ◽

Vol 697 ◽

pp. 572-575

Author(s):

Xue Qing Yang ◽

Nai Peng ◽

Cheng Ji Deng

Keyword(s):

Activation Energy ◽

Apparent Activation Energy ◽

Isothermal Kinetics ◽

Nitridation Reaction ◽

Result Show ◽

Different Temperatures ◽

Two Stages ◽

Kinetics Of ◽

And Diffusion

The kinetics of in-situ β- Sialon bonded Al2O3-C (SAC) refractories were investigated by TGA techniques via isothermal nitridation experiments at different temperatures. The result show that the nitridation process of in-situ β-Sialon bonded Al2O3-C refractories can be divided into two stages: the nitridation reaction rate controlling stage in the first 10 min, and the apparent activation energy of nitridation reaction is 370 kJ/mol ; then the reaction is controlled by both chemical reaction and diffusion rate in the following 110 min, the apparent activation energy of nitridation reaction is 410 kJ/mol.

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Modelling the Kinetics of Color and Texture Changes of Dabai (Canarium odontophyllum Miq.) during Blanching

Agronomy ◽

10.3390/agronomy11112185 ◽

2021 ◽

Vol 11 (11) ◽

pp. 2185

Author(s):

Rosnah Shamsudin ◽

Siti Hajar Ariffin ◽

Wan Nor Zanariah Zainol @Abdullah ◽

Nazatul Shima Azmi ◽

Arinah Adila Abdul Halim

Keyword(s):

Kinetic Models ◽

Color Difference ◽

Hot Water ◽

Fractional Conversion ◽

Conversion Model ◽

First Order ◽

Side Dish ◽

Different Temperatures ◽

Canarium Odontophyllum ◽

Kinetics Of

Dabai (Canarium odontophyllum Miq.) is a fruit that is often eaten by first blanching in hot water to make the flesh creamier and softer, before it is served as a snack or side dish. In this study, Dabai fruit was blanched at different temperatures between 60 and 100 °C, with an increment of 10 °C, for up to 10 min, and the kinetics of quality changes (color and texture) were studied. Kinetic models that were assessed for changes of color and texture were zero-order, first-order, and fractional conversion model. The results showed that L parameter had no change throughout the blanching process, while parameters a*, b*, chroma (C), and total color difference (TCD) resulted as significantly increased as the temperature and duration of blanching increased. However, the change of firmness was not significant due to minor changes of firmness as the temperature and time increased. In terms of kinetic models, zero and fractional-conversion order well described the changes of a* parameter; while zero, first and fractional conversion well described parameters b*, C and TCD. Change of firmness did not fit with zero or first-order. All of the kinetic models obeyed the Arrhenius equation. Thus, the fitted kinetic models can be used to design the blanching process of Dabai fruit.

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A study of kinetics and successive sorption/desorption of Zn and Cd uptake onto iron-modified zeolite

Clay Minerals ◽

10.1180/claymin.2015.050.1.11 ◽

2015 ◽

Vol 50 (1) ◽

pp. 117-132 ◽

Cited By ~ 2

Author(s):

Marin Ugrina ◽

Nediljka Vukojević Medvidović ◽

Jelena Perić ◽

Marina Trgo

Keyword(s):

Electrolyte Solutions ◽

Approximation Model ◽

Diffusion Kinetic ◽

Cd Uptake ◽

Modified Zeolite ◽

Rate Limiting Step ◽

Intra Particle Diffusion ◽

Rate Limiting ◽

Kinetics Of ◽

And Diffusion

AbstractThe sorption properties of iron-modified zeolite (IMZ) and the kinetics of zinc and cadmium uptake by the IMZ were investigated by the batch method. Two kinetic stages were observed, fast uptake up to 240 min, followed by slow uptake up to equilibrium. Kinetic results were fitted to the reaction and diffusion kinetic models, which indicated that intra-particle diffusion was the rate-limiting step. The Vermeulen’s approximation model was used to predict the quantity of Zn and Cd ions removed per gram of IMZ. The results of the successive sorption and desorption of Zn and Cd ions, with different electrolyte solutions, showed the best desorption efficiency with sodium salt solutions. Four successive repetitions of the sorption/desorption cycles showed a small difference between the amount of sorbed and desorbed Zn and Cd ions from the second to the fourth cycle. This indicates excellent sorption/regeneration properties of the IMZ.

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Effects of ball-milling conditions and additives on the hydrogen sorption properties of Mg + 5 wt% Cr2O3 mixtures

Journal of Materials Research ◽

10.1557/jmr.2006.0206 ◽

2006 ◽

Vol 21 (7) ◽

pp. 1747-1752 ◽

Cited By ~ 7

Author(s):

J-L. Bobet ◽

M. Kandavel ◽

S. Ramaprabhu

Keyword(s):

Particle Size ◽

Sorption Process ◽

Rate Equations ◽

Desorption Kinetics ◽

Yield Information ◽

Order Of Magnitude ◽

Effect Of Particle Size ◽

Kinetics Of ◽

And Diffusion

Effects of particle size of Cr2O3 catalyst on the hydrogen absorption/desorption kinetics of Mg + 5 wt% Cr2O3 mixtures have been studied. To explain the effect of particle size of Cr2O3 and also to yield information about the role of Cr2O3 during the sorption process, the kinetics data have been analyzed using Avrami–Erofeev rate equations. The activation energies and diffusion coefficients of these mixtures are in the ranges of 50.6–63.2 kJ/mol and 1.2.10−11 to 8.9.10−10 cm2/s, respectively. The addition of nano-oxides led to an increase of the diffusion coefficient of hydrogen by one order of magnitude.

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Study on the Oxidation Kinetics of In Situ β-Sialon Bonded Al2O3-C Refractories

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.881-883.1021 ◽

2014 ◽

Vol 881-883 ◽

pp. 1021-1025 ◽

Cited By ~ 3

Author(s):

Bin Xu ◽

Hong Xi Zhu ◽

Nai Peng ◽

Cheng Ji Deng ◽

Wen Jie Yuan

Keyword(s):

Oxidation Rate ◽

Reaction Rate ◽

Diffusion Rate ◽

Isothermal Oxidation ◽

Different Temperatures ◽

Rate Controlled ◽

Kinetics Of ◽

And Diffusion ◽

Oxidation Behaviors

The oxidation behaviors and kinetics of in-situ β-Sialon bonded Al2O3-C refractories were investigated by TGA techniques via isothermal oxidation experiments at different temperatures. The results show that the oxidation process of in-situ β-Sialon bonded Al2O3-C refractories can be divided into three stages: oxidation reaction rate controlling stage, reaction and diffusion controlling stage, and diffusion controlling stage. The oxidation rate controlled by the reaction rate has no obvious changes as the temperature increases. The oxidation rate controlled by the reaction rate and the diffusion rate together has a trend of decline, so is the oxidation rate controlled by the diffusion rate.

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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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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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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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