Assessment of the loss of radioactive isotopes from waste solids to the environment. Part I. Background and theory

Godbee, H.W.; Joy, D.S.

doi:10.2172/4118334

Cited by 60 publications

(38 citation statements)

References 4 publications

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“…For the monolithic material this approach results in analytical expressions for the contaminant concentration in leachant and material versus time. For small 4D,f/b2 (1 + S/K,L), the solution can be simplified, yielding the original expressions of [5].…”

Section: Discussionmentioning

confidence: 99%

“…(16) has been substituted. This result was first obtained by [5] and is used in [3]. In both references psCs, is replaced by the equivalent quotient M,,/V, whereby M,, is the contaminant mass initially present in the monolith.…”

Section: Leaching Of An Immersed Materialsmentioning

confidence: 99%

“…[5] were the first to derive a model for the leaching of monoliths. This model was based on the solution of the second order diffusion model of a semiinfinite medium.…”

Section: Introductionmentioning

confidence: 99%

“…For the monolith leaching the present approach yields a solution in closed form for the contaminant concentrations in monolith and leachant as a function of time. Furthermore, it is demonstrated that for a special case the expressions can be simplified to the standard equations of [5]. The granular materials leaching model yields original analytic expressions for the concentrations in monolith and leachant.…”

Section: Introductionmentioning

confidence: 99%

“…The governing equations are solved in closed form, yielding the contaminant concentration in leachant and monolith versus the elapsed time. For special cases this solution corresponds to the leaching expressions obtained by Godbee and Joy (1974). Subsequently, the unsteady leaching process from a granular material packed in a column, flushed by a leachant, is modeled.…”

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confidence: 99%

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Leaching models for multiple immersed materials and for granular materials flushed in a column

Brouwers¹

1997

Journal of Hazardous Materials

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The present paper addresses the leaching of hazardous contaminants from immersed and replenished materials and from granular materials flushed in a column. First, the leaching of an immersed material in contact with a limited volume of leachant is studied. The mass transfer from material to leachant is assumed to he inversely proportional to Jt (i.e. following the semiinfinite medium diffusion model). The leaching model accounts for the concentration of the contaminant in the leachant, the (deviation from) equilibrium partition of the contaminant between material and leachant, and leachant replenishment. The governing equations are solved in closed form, yielding the contaminant concentration in leachant and monolith versus the elapsed time. For special cases this solution corresponds to the leaching expressions obtained by Godbee and Joy (1974). Subsequently, the unsteady leaching process from a granular material packed in a column, flushed by a leachant, is modeled. Here, the mass transfer from material to leachant is also assumed as inversely proportional to \lt. The model leads to a moving boundary problem, the governing partial differential equations are transformed and solved using asymptotic techniques. Approximate expressions are obtained for the contaminant concentration of the material and in the leachant. Of special practical interest is the leachant concentration at the exit of the column as here the leachant can be collected in flasks and analyzed. Finally, the models are generalized to systems where the mass transfer is an arbitrary power function of time. The resulting equations can for instance he used for determining an effective diffusion coefficient and/or comparing immobilization yields. 0 1997 Elsevier Science B.V.

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Section: Discussionmentioning

confidence: 99%

Section: Leaching Of An Immersed Materialsmentioning

confidence: 99%

“…[5] were the first to derive a model for the leaching of monoliths. This model was based on the solution of the second order diffusion model of a semiinfinite medium.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Leaching models for multiple immersed materials and for granular materials flushed in a column

Brouwers¹

1997

Journal of Hazardous Materials

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Interaction of La³⁺ and Ce⁴⁺ with polyethylene and polypropylene polymeric matrices

Ibrahim¹,

Khalil²,

El-Gammal³

2006

J of Applied Polymer Sci

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ABSTRACT:The different modes of interaction of La 3þ and Ce 4þ as simulated radioactive lanthanides found in the backend of the nuclear fuel cycle with polyethylene and polypropylene macromolecules were considered. The various compositions were characterized before and after irradiation at different gamma ray doses. The mechanical properties including stress-strain parameters were also tested. The morphological and mechanical behaviors of the various composites were different from those of the corresponding pure polymers and affected by the chemistry of the interacting elements. Besides, the leaching characteristics were carried out using the short-and long-term procedure; the leaching rates were evaluated as an index for immobilization of these lanthanides. Two semiempirical models were applied to find out the dominant leaching mechanism of La 3þ and Ce 4þ. Dissolution associated with diffusion was the dominant leaching path and the elemental leaching characteristics depended upon its solubility in water. Diffusion coefficients and dissolution rate constants, the main parameters in the long-term prediction model, were obtained using short-and long-term experimental data. The model was found to be useful in predicting the long-term behavior of such elements to assess the stability of the used waste forms.

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Effects of pH on leaching behavior of compacted cement solidified/stabilized lead contaminated soil

Wang

Xue

et al. 2015

Env Prog and Sustain Energy

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The compacted cement stabilized/solidified (S/S) metal contaminated soil could be used for “controlled utilization,” such as road base, quarry rehabilitation, and lagoon closure. However, the complexity and variability of environment, especially the acid rain and alkaline leachate, greatly influence the leaching behaviors of S/S heavy metal contaminated soil and threaten the environment. The leaching characteristics of the compacted S/S samples were investigated over a wide range of pH (2.65, 3.65, 5.00, 7.00, and 10.00). Semidynamic leaching tests were conducted to evaluate the effects of pH on effectiveness and controlling leaching mechanism of compacted cement S/S treated lead (Pb) contaminated soil. Results showed that there was no obviously change of the cumulative fraction of Pb leached (CFL) in weak acid or weak alkaline conditions (pH ranging from 5.00 to 10.00), and the strong acid significantly altered the leaching behaviors of Pb. The calculated values of effective diffusion coefficient (De) and leachability index (LX) indicated that the mobility of Pb2+ was weak and the compacted S/S treatment could be used for “controlled utilization” with environment pH value ranging from 3.65 to 10.00. Especially, the LX value was 8.49 when the compacted S/S sample was immersed in the leachant with pH 2.65, indicated that the S/S sample was not considered appropriate for disposal. The mechanism controlling Pb2+ leaching from S/S samples at all the pH range (2.65–10.00) appeared to be diffusion, and with pH decreasing in acid conditions, the controlling leaching mechanism somehow was changing from diffusion to surface wash‐off. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 149–155, 2016

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Assessment of the loss of radioactive isotopes from waste solids to the environment. Part I. Background and theory

Abstract: 1. Introduction 2 2. Graphical Methods for Reporting the Results of Leach Tests as a Function of Time h 3. Analytical Methods for Reporting and Extrapolating the Results of Leach Tests as a Function of Time 11 3.

Cited by 60 publications

References 4 publications

Leaching models for multiple immersed materials and for granular materials flushed in a column

Leaching models for multiple immersed materials and for granular materials flushed in a column

Interaction of La³⁺ and Ce⁴⁺ with polyethylene and polypropylene polymeric matrices

Effects of pH on leaching behavior of compacted cement solidified/stabilized lead contaminated soil

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Assessment of the loss of radioactive isotopes from waste solids to the environment. Part I. Background and theory

Abstract: 1. Introduction 2 2. Graphical Methods for Reporting the Results of Leach Tests as a Function of Time h 3. Analytical Methods for Reporting and Extrapolating the Results of Leach Tests as a Function of Time 11 3.

Cited by 60 publications

References 4 publications

Leaching models for multiple immersed materials and for granular materials flushed in a column

Leaching models for multiple immersed materials and for granular materials flushed in a column

Interaction of La3+ and Ce4+ with polyethylene and polypropylene polymeric matrices

Effects of pH on leaching behavior of compacted cement solidified/stabilized lead contaminated soil

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Product

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Interaction of La³⁺ and Ce⁴⁺ with polyethylene and polypropylene polymeric matrices