Ion exchange column studies for the selective separation of radionuclides using the hydrous crystalline silicotitanante, UOP IONSIV® IE-911 /
During the Cold War, large amounts of nuclear waste were generated from nuclear arms production. The radioactive ions in these wastes pose significant disposal difficulties. Recently, through collaborative efforts at Texas A&M University and Sandia National Laboratories, an ion exchange material...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1999.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=733675811&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | During the Cold War, large amounts of nuclear waste were generated from nuclear arms production. The radioactive ions in these wastes pose significant disposal difficulties. Recently, through collaborative efforts at Texas A&M University and Sandia National Laboratories, an ion exchange material, TAM-5, was synthesized that selectively removes Cs and Sr from these concentrated waste streams (Anthony et a1., 1993). UOP IONSIV® IE-911, the commercial form of TAM-5, was selected as a leading technology for radioactive waste treatment at Department of Energy (DOE) storage sites. IE-911 would be utilized in a fixed-bed column to treat these wastes. A mathematical model of the ion exchange column has been developed considering the IE-911 equilibrium behavior, dimensional resistance within the granules, axial dispersion within the column, and film dimensional resistance around the granules. Fundamentally, these factors can be measured from independent experiments and implemented in a column model to simulate performance. The aim of this study was to determine the suitability of an ion exchange column model which implements the two-phase homogeneous particle material balance for simulating IE- 911 performance in fixed-beds. Model parameters were determined from independent experiments or literature correlations. Equilibrium data were fit with the Langmuir isotherm and the Suzuki and Smith (1972) correlation was used to estimate axial dispersion. Diffusion coefficients were estimated from batch kinetic studies (Gu et a1., 1997; Huckman, 1999). The film mass transfer coefficient was determined from the Wilke and Hougen (1945) correlation. The proposed column model was used to simulate experimental column breakthrough data. Batch diffusivities provided reasonable, conservative fits to the data, but usually some adjustment was required to better fit the breakthrough curve shape. In solutions with Na levels from 1- to 5.7-M Na, Cs diffusivities for the several different IE-911 batches studied were on the order of 10⁻¹¹ m²/s in agreement with the batch results of Gu et at. (1997) and Huckman (1999). The two-phase homogeneous column model proved sufficient for designing commercial-scale ion exchange units that utilize IE-911. The experimental results and simulations provide guidelines and suggestions for model parameters to accurately predict IE-911 column performance. |
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| Item Description: | Vita. "Major Subject: Chemical Engineering". In title, symbols are used. |
| Physical Description: | xii, 115 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 109-114). |