scholarly journals Study of Pu(IV) and Am(III) sorption to clay minerals: laboratory experiments and modeling

2011 ◽  
Vol 1 (1) ◽  
pp. 237-244
Author(s):  
G. Lujanienė ◽  
P. Beneš ◽  
K. Štamberg ◽  
D. Vopalka ◽  
E. Radžiūtė
Keyword(s):  
Experimental Data ◽  
Ion Exchange ◽  
Clay Minerals ◽  
Iron Oxides ◽  
Laboratory Experiments ◽  
Background Electrolyte ◽  
Surface Complexation ◽  
Sorption Behavior ◽  
Natural Clay ◽  
Sorption Mechanisms

Abstract Sorption of Pu(IV) and Am(III) to natural clay from a mixture of synthetic rainwater — cement water was studied by batch and sequential extraction experiments as a function of pH and ionic strength These experiments were intended to simulate the effect of cement dissolution, causing the release of K+, Ca2+ and other cations from solidified radioactive waste into the aqueous phass. The results indicated a complex sorption behavior of the elements studied. It was found that iron oxides play an important role in the uptake of Pu(IV), whereas ion exchange and CaCO3 are mainly responsible for the binding of Am(III) on the clay. Simplified sorption experiments were conducted with clay minerals and iron oxides, using 0.01 and 0.1 mol/L NaNO3 as background electrolyte under an Ar atmosphere, for a better understanding of the sorption mechanisms. The experimental data were interpreted using the combination of surface complexation and ion-exchange models.

Sorption of Cs, Ni, Pb, Eu(III), Am(III), Cm, Ac(III), Tc(IV), Th, Zr, and U(IV) on MX 80 bentonite: An experimental approach to assess model uncertainty

2006 ◽  
Vol 94 (9-11) ◽  
Author(s):  
Bernd Grambow ◽  
Massoud Fattahi ◽  
Gilles Montavon ◽  
C. Moisan ◽  
E. Giffaut
Keyword(s):  
Experimental Data ◽  
Ion Exchange ◽  
Model Uncertainty ◽  
Mineral Assemblage ◽  
Experimental Approach ◽  
Surface Complexation ◽  
Fission Products ◽  
Exchange Model ◽  
Dissolution Properties

A multi-site surface complexation/ion exchange model for dispersed MX 80 bentonite has been calibrated, considering the dissolution properties of the constituting mineral assemblage, for sorption of a large number of radionuclides, using experimental data from the present study together with well constrained literature data. Emphasis was on tri- and tetravalents actinides and fission products and reducing groundwater compositions.

Effect of sulfate on sorption of Eu(III) by Na-montmorillonite

2019 ◽  
Vol 107 (2) ◽  
pp. 115-128
Author(s):  
Madhuri A. Patel ◽  
Aishwarya Soumitra Kar ◽  
Sumit Kumar ◽  
Mrinal Kanti Das ◽  
Vaibhavi V. Raut ◽  
...  
Keyword(s):  
Surface Complexation ◽  
Sorption Process ◽  
Dominant Mode ◽  
High Level Waste ◽  
Sorption Behavior ◽  
Natural Clay ◽  
Surface Complexation Modeling ◽  
Buffer Material ◽  
High Level ◽  
Mechanism Of Sorption

Abstract Smectite-rich natural clay is being evaluated as the backfill and buffer material in the Indian repository program for the nuclear high level waste disposal. In the natural clay, montmorillonite is one of the major mineral component governing the sorption behavior of various radionuclides. In the present work, influence of sulfate anion on sorption of Eu(III) by Na-montmorillonite has been investigated. The effect of pH and sulfate concentration on Eu(III) sorption by Na-montmorillonite was used to understand the mechanism of sorption process. The Eu(III) sorption by clay at varying pH was virtually pH independent at lower pH (<4), with ion exchange as the dominant mode for Eu(III) sorption. In the pH region of 4–6.5, sharp increase in sorption indicates surface complexation as predominant mechanism. At pH>6.5, the sorption attained a constant value. To deduce the mechanism of sorption of Eu(III) on Na-montmorillonite surface in presence of sulfate, ATR-FTIR spectroscopic investigations has been carried out which indicate the presence of sulfate bearing species on Na-montmorillonite surface. Using spectroscopic findings as a guide, the surface complexation modeling, in absence and presence of sulfate, was successfully carried out.

Removal of ammonia by natural clay minerals using fixed and fluidised bed column reactors

2001 ◽  
Vol 1 (1) ◽  
pp. 81-88 ◽  
Author(s):  
M.S. Çelik ◽  
B. Özdemir ◽  
M. Turan ◽  
I. Koyuncu ◽  
G. Atesok ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Clay Minerals ◽  
Fixed Bed ◽  
Water Reservoir ◽  
Fluidised Bed ◽  
Raw Water ◽  
Natural Clay ◽  
Exchange Column ◽  
Ion Exchange Column ◽  
Synthetic Water

A series of fixed and fluidised bed ion exchange column runs were conducted to identify the ability of natural clay minerals, sepiolite and clinoptilolite, to remove ammonia from a contaminated drinking water reservoir. Ion exchange column tests using both fixed and fluidised bed were initially carried out with synthetic water composed of NH4Cl. Breakthrough curves as a function of flow rate, particle size, and initial ammonia concentration reveal that sepiolite does not have as high ion exchange capacity as clinoptilolite but maintains a steady adsorption up to higher bed volumes. The adsorption capacity was modified by using regeneration cycles at both acidic and alkaline pH. Furthermore, fluidised bed runs with clinoptilolite utilising water and air as fluidiser resulted in inferior results compared to those of fixed bed runs. This was respectively ascribed to the presence of ammonia in the circulating water and competition of exchangeable ions released in water and the ability of air to adsorb nitrogen. Tests conducted with natural raw water contaminated with sewage indicated that clinoptilolite adsorbs ammonia the same as the synthetic water. Regenerated clinoptilolite is capable of removing ammonia from both synthetic and actual raw water at a much higher rate than the untreated clinoptilolite.

Equilibrium Sorptions in Heterogeneous Ion Exchange Membranes

1992 ◽  
Vol 57 (9) ◽  
pp. 1905-1914
Author(s):  
Miroslav Bleha ◽  
Věra Šumberová
Keyword(s):  
Experimental Data ◽  
Ion Exchange ◽  
Total Content ◽  
Distribution Coefficients ◽  
Exchange Capacity ◽  
Ion Exchange Membranes ◽  
Ion Exchange Capacity ◽  
Equilibrium Sorption ◽  
Inhomogeneity Factor

The equilibrium sorption of uni-univalent electrolytes (NaCl, KCl) in heterogeneous cation exchange membranes with various contents of the ion exchange component and in ion exchange membranes Ralex was investigated. Using experimental data which express the concentration dependence of equilibrium sorption, validity of the Donnan relation for the systems under investigation was tested and values of the Glueckauf inhomogeneity factor for Ralex membranes were determined. Determination of the equilibrium sorption allows the effect of the total content of internal water and of the ion-exchange capacity on the distribution coefficients of the electrolyte to be determined.

scholarly journals Modelling time efficiency of cobot-supported kit preparation

2019 ◽  
Vol 106 (5-6) ◽  
pp. 2227-2241 ◽  
Author(s):  
Patrik Fager ◽  
Martina Calzavara ◽  
Fabio Sgarbossa
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Cycle Time ◽  
Laboratory Experiments ◽  
Spare Parts ◽  
Batch Preparation ◽  
Assembly Quality ◽  
Numerical Example ◽  
Business To Business ◽  
Support Time

AbstractKitting – meaning to supply assembly with components in presorted kits – is widely seen as beneficial for assembly quality and efficiency when there is a multitude of component variants. However, the process by which kits are prepared – the kit preparation – is labour-intensive, and kit errors are problematic at assembly processes. The use of robotics to support kit preparation has received some attention by researchers, but literature is lacking with respect to how collaborative robots – cobots – can support kit preparation activities. The purpose of this paper is to identify the potential of a cobot to support time-efficient batch preparation of kits. To address the purpose, the paper presents a mathematical model for estimation of the cycle time associated with cobot-supported kit preparation. The model is applied in a numerical example with experimental data from laboratory experiments, and cobot-supported kit preparation is compared with manual kit preparation. The findings suggest that cobot-supported kit preparation is beneficial with diverse kits and smaller components quantities per SKU (Stock Keeping Unit) and provides less variability of the outcome, when compared to manual kit preparation. The paper reveals several insights about cobot-supported kit preparation that can be valuable for both academics and practitioners. The model developed can be used by practitioners to assess the potential of cobots to support kit-batch preparation in association with assembly, spare parts, repair and maintenance, or business to business industry.

Experimental data and assessment of predictive modeling for radium ion-exchange on beidellite, a swelling clay mineral with a tetrahedral charge

2017 ◽  
Vol 85 ◽  
pp. 1-9 ◽  
Author(s):  
Valentin Robin ◽  
Emmanuel Tertre ◽  
Catherine Beaucaire ◽  
Olivier Regnault ◽  
Michael Descostes
Keyword(s):  
Experimental Data ◽  
Ion Exchange ◽  
Clay Mineral ◽  
Predictive Modeling ◽  
Swelling Clay
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