scholarly journals Equilibrium and Kinetics of U(VI)aq Adsorption on in situ Generated Fe2O3. nH2O

2019 ◽  
Vol 70 (10) ◽  
pp. 3482-3485
Author(s):  
Ioana Carmen Popescu (Hostuc) ◽  
Ligia Stoica ◽  
Carolina Constantin ◽  
Ana Maria Stanescu
Keyword(s):  
Kinetic Modelling ◽  
Sorption Process ◽  
Second Order ◽  
Chemical Component ◽  
Isotherm Models ◽  
Sorption Equilibrium ◽  
Equilibrium And Kinetics ◽  
Pseudo Second Order ◽  
Kinetics Of

The paper aims to present research results obtained at the study of equilibrium and kinetics of U(VI)aq sorption on in situ generated Fe2O3 x nH2O from model solutions. The studied systems represent U(VI) solutions with CU(VI) = 5-30 mg�L-1 for which maximum U(VI) removal efficiencies (%RU(VI) = 95.98) on in situ generated Fe2O3��nH2O were obtained in the following working conditions: pH = 8.75, tcontact = 30 min, [U(VI)] : [Fe(III)] =1:75 and stirring rate 250 RPM. The Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models were used to study U(VI) sorption equilibrium. Langmuir isotherm with the correlation coefficient R2 (0.9808) suggests that it involves physical interactions. Freundlich (R2 = 0.8349) and Temkin (R2 = 0.8715) models describe well the sorption process suggesting that there also exists a chemical component, complexing and/or co-precipitation. The kinetic modelling according to the pseudo-first and pseudo-second order models, respectively has demonstrated that the U(VI) sorption equilibrium follows the pseudo-second order equation suggesting a chemical component of the process.

scholarly journals Equilibrium and Kinetics of U(VI)aq Adsorption on in situ Generated Fe2O3. nH2O

2019 ◽  
Vol 70 (10) ◽  
pp. 3482-3485
Keyword(s):  
Kinetic Modelling ◽  
Sorption Process ◽  
Second Order ◽  
Chemical Component ◽  
Isotherm Models ◽  
Sorption Equilibrium ◽  
Equilibrium And Kinetics ◽  
Pseudo Second Order ◽  
Kinetics Of

The paper aims to present research results obtained at the study of equilibrium and kinetics of U(VI)aq sorption on in situ generated Fe2O3 x nH2O from model solutions. The studied systems represent U(VI) solutions with CU(VI) = 5-30 mg·L-1 for which maximum U(VI) removal efficiencies (%RU(VI) = 95.98) on in situ generated Fe2O3’”nH2O were obtained in the following working conditions: pH = 8.75, tcontact = 30 min, : =1:75 and stirring rate 250 RPM. The Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models were used to study U(VI) sorption equilibrium. Langmuir isotherm with the correlation coefficient R2 (0.9808) suggests that it involves physical interactions. Freundlich (R2 = 0.8349) and Temkin (R2 = 0.8715) models describe well the sorption process suggesting that there also exists a chemical component, complexing and/or co-precipitation. The kinetic modelling according to the pseudo-first and pseudo-second order models, respectively has demonstrated that the U(VI) sorption equilibrium follows the pseudo-second order equation suggesting a chemical component of the process. Keywords: uranium, sorption/precipitate flotation, adsorption isotherms modelling, kinetics

scholarly journals Equilibrium and Kinetic Study of Ammonium Sorption by Raphia farinifera

2019 ◽  
Vol 230 (10) ◽  
Author(s):  
Paweł Staroń ◽  
Paulina Sorys ◽  
Jarosław Chwastowski
Keyword(s):  
Chemical Nature ◽  
Sorption Process ◽  
Sorption Kinetics ◽  
Second Order ◽  
Isotherm Models ◽  
Mechanism Analysis ◽  
Order Model ◽  
Sorption Model ◽  
Pseudo Second Order ◽  
Kinetics Of

Abstract The study investigated the sorption capacity of biosorbent-raphia sp. against ammonia. Raphia fibers were used without and with the modification of its surface with NaCl, NaNO3, and K2SO4. The data was analyzed in the state of equilibrium using four isotherm models such as Langmuir, Freudlich, Temkin, and Dubinin-Radushkevich. The equilibrium of ammonia sorption for all studied systems was best described by the Freudlich isotherm model. On its basis, it can be assumed that the studied process is of chemical nature, which results from the value of the coefficient 1/n < 1. In order to confirm the sorption mechanism, analysis of the kinetics of the ammonia sorption process on raphia fibers was performed. Four kinetic models of sorption were calculated: pseudo-first-order model, pseudo-second-order model, Elovich model, and Webber-Morris intermolecular diffusion model. The sorption kinetics of the modeled ammonia waste were carried out using unmodified palm fibers and all kinds of surface modification. This process was best described by the pseudo-second-order sorption model, which can be considered as a confirmation of the chemical nature of ammonia sorption on raphia sp. fibers.

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

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
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.

Lead (II) Pollution Enhances the Binding of Transgenic Toxin in Brown and Red Soils: Equilibrium and Kinetics

2013 ◽  
Vol 11 (1) ◽  
pp. 501-509
Author(s):  
Xueyong Zhou ◽  
Huifen Liu ◽  
Xianzhi Lu ◽  
Lili Shi ◽  
Jianchao Hao
Keyword(s):  
Genetically Modified Crops ◽  
Red Soil ◽  
Second Order ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Free Energy Of Adsorption ◽  
Intraparticle Diffusion Model ◽  
Equilibrium And Kinetics ◽  
Equilibrium Data ◽  
Pseudo Second Order

Abstract Genetically modified crops, which produce insecticidal toxins from Bacillus thuringiensis (Bt), release the toxins into soils. Although the phenomena of persistence and degradation of Bt toxins have been documented, the effect of heavy metals on the fate of these toxins in soil has not yet been elucidated. The effect of Pb(II) on the adsorption behaviors of Bt toxin in brown and red soil was investigated. With the increase of Pb(II) concentration, the adsorption of Bt toxin in brown and red soil increased. The Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherm models gave better fitting to the experimental equilibrium data. Values of KL, KF and n increased but RL decreased with the increase of Pb(II) concentration, showing that the Pb(II) promoted the adsorption of Bt toxin in soils. The mean free energy of adsorption (E) ranged from 10.43 to 16.44 kJ mol−1 may correspond to a chemical ion-exchange mechanism. Three kinds of kinetic models, the pseudo-first-order, pseudo-second-order and intraparticle diffusion model, were used to test the experimental data. The results showed that the adsorption of Bt toxin by brown and red soil followed the pseudo-second-order kinetic model. The addition of Pb(II) during the adsorption led to a decrease of the desorption of Bt toxin from soils, indicating that the residual risk of Bt toxin may become larger if soil is polluted by lead.

Zinc Adsorption Property of Gamma-MnO2 Nanostructure: Equilibrium and Kinetic Studies

2016 ◽  
Vol 708 ◽  
pp. 3-8
Author(s):  
Van Phuc Dinh ◽  
Ngoc Chung Le ◽  
Thi Phuong Tu Nguyen ◽  
Thi Dong Thuong Hoang ◽  
Van Dong Nguyen ◽  
...  
Keyword(s):  
Adsorption Property ◽  
Kinetic Studies ◽  
Sorption Process ◽  
Second Order ◽  
Isotherm Models ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
The Mean ◽  
Influence Of Ph ◽  
Sorption Time

In this work, gamma–MnO2 nanostructure was used as a sorbent to remove Zn (II) ion from aqueous solution. The influence of pH, sorption time and Zn (II) ion initial concentration were examined. The results showed that equilibrium adsorption was obtained after 60 minutes with 240 rpm of shaking speed at pH = 4.0. The experimental data were analyzed using five non-linear isotherm models: Langmuir, Freundlich, Sips, Tempkin and Dubinin – Radushkevich. The adsorption capacity (qm) from the Langmuir isotherm model for Zn (II) is founded as 55.23 mg/g. The heat of sorption process and the mean free energy were estimated from Temkin and Dubinin – Redushkevich isotherm models to be less than 8 kj/mol which vividly proved that the adsorption experiment followed a physical process. Kinetic studies have shown that although the adsorption data partially followed pseudo-first-order and pseudo-second-order equation for different time, it was well expressed by pseudo-second-order model.

scholarly journals Application of Kinetic Models to the Sorption of Copper(II) on to Peat

2002 ◽  
Vol 20 (8) ◽  
pp. 797-815 ◽  
Author(s):  
Y.S. Ho ◽  
G. McKay
Keyword(s):  
Sorption Capacity ◽  
Fractional Power ◽  
Sorption Process ◽  
Order Equation ◽  
Second Order ◽  
Process Models ◽  
Elovich Equation ◽  
Pseudo Second Order ◽  
High Degree ◽  
Kinetics Of

A comparison of the kinetics of the sorption of copper(II) on to peat from aqueous solution at various initial copper(II) concentrations and peat doses was made. The Elovich model and the pseudo-second order model both provided a high degree of correlation with the experimental data for most of the sorption process. There was a small discrepancy at the initial stages of sorption which suggested that film diffusion or wetting of the peat may be involved in the early part of the sorption process. Models evaluated included the fractional power equation, the Elovich equation, the pseudo-first order equation and the pseudo-second order equation. The kinetics of sorption were followed based on the sorption capacity of copper(II) on peat at various time intervals. Results show that chemical sorption processes may be rate-limiting in the sorption of copper(II) on to peat during agitated batch contact time experiments. The rate constant, the equilibrium sorption capacity and the initial sorption rate were calculated. From these parameters, an empirical model for predicting the concentrations of metal ions sorbed was derived.

Studies on removal of chromium (VI) from water using chitosan coated Cyperus pangorei

2010 ◽  
Vol 62 (10) ◽  
pp. 2435-2441 ◽  
Author(s):  
R. Malarvizhi ◽  
Y. Venkateswarlu ◽  
V. Ravi babu ◽  
S. Syghana Begum
Keyword(s):  
Metal Ion ◽  
Sorption Process ◽  
Second Order ◽  
Isotherm Models ◽  
Initial Contact ◽  
Order Kinetic ◽  
Toxic Heavy Metals ◽  
Batch Mode ◽  
Chromium Vi ◽  
Pseudo Second Order

Environmental contamination by toxic heavy metals is a significant universal problem. The main objective of the study is to use a biodegradable materials like Cyperus pangorei and Chitosan as a composite biosorbent for the removal of Cr(VI) from water. The newly prepared biosorbent is characterized and the capacity of Cr(VI) removal of the biosorbent is carried out systematically by batch mode operations. The adsorption capacity of the biosorbent is examined by changing the parameters like biosorbent dose, varying the initial contact time, varying initial concentration of metal ion and pH of the metal ion solution to know the actual mechanism taking place during the initial sorption process. The experimental data obtained were fitted with the Freundlich, Langmuir and Redlich–Peterson isotherm models and the pseudo first order and the pseudo second order kinetic models. Equilibrium data were fitted very well to the Langmuir Isotherm model and pseudo second order kinetic model. Desorption of the metal ion is also carried out using different concentration of NaOH.

scholarly journals Biosorption of praseodymium (III) using Terminalia arjuna bark powder in batch systems: isotherm and kinetic studies

2017 ◽  
Vol 77 (3) ◽  
pp. 727-738 ◽  
Author(s):  
Krishna Kumari Swain ◽  
Pravat Manjari Mishra ◽  
Aparna Prabha Devi
Keyword(s):  
Kinetic Studies ◽  
Second Order ◽  
Advanced Materials ◽  
Isotherm Models ◽  
Terminalia Arjuna ◽  
Biosorption Process ◽  
Batch Systems ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Kinetics Of

Abstract The high demand for rare earth elements (REEs) used in various advanced materials implies demand for increased production of REEs or the recycling of solutions to recover the REEs they contain. In this study, the biosorption of Pr(III) from aqueous solution by bark powder of Terminalia arjuna was examined in a batch system as a function of metal concentration, biosorbent dosage, pH and contact time. Results showed that T. arjuna bark powder has a high affinity for adsorbing Pr(III): more than 90% at pH 6.63. The adsorption of Pr(III) by T. arjuna bark powder was investigated by the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. The kinetics of the biosorption process was tested with pseudo-first-order and pseudo-second-order models, and the results showed that the biosorption process was better fitted to the pseudo-second-order model. From Fourier transform infrared spectroscopy (FT-IR) analysis, it is confirmed that the biomolecules of T. arjuna bark powder are involved in the biosorption process of Pr(III) metal ions.

Sign in / Sign up

Export Citation Format

Share Document