| Autor: |
R. A. Da Silva Neves, M. Streat, C. D. Barnes |
| Rok vydání: |
2007 |
| Předmět: |
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| Zdroj: |
Journal of Applied Chemistry and Biotechnology. 24:787-801 |
| ISSN: |
0375-9210 |
| Popis: |
The ion exchange kinetics of uranium sorption from acidic sulphate solutions onto weak and strong base resins has been studied. In order to facilitate experimentation and analysis, isotopic redistribution experiments of uranyl sulphate ions (with U-235 as a tracer) under conditions of particle diffusion control have been performed. Also, self-diffusion experiments for sulphate ions (with S-35 as a tracer) and counter diffusion measurements involving uranyl sulphate-sulphate exchange have been performed. The ion exchange of uranium is a slow reaction and appears to be particle diffusion controlled at all solution conditions of practical interest. For a weak base resin (Relite MG-1), the self-diffusion coefficient of uranyl sulphate ions changes with particle size, increasing from 1.49 to 4.88 × 10−9 cm2/s as the particle diameter is reduced from 0.146 to 0.054 cm. With a strong base resin (Dowex-1×8), the self-diffusion coefficient of uranyl sulphate ions remains reasonably constant with varying particle diameter at a value of 1.76 × 10−9 cm2/s. Sulphate ion self-diffusion coefficients were also constant with particle size (2.50 × 10−7 cm2/s) and the counter exchange diffusivity lies between the values for the individual species; a typical value is 1.53 × 10−8 cm2/s. It is argued that resin matrix structure has a significant effect on uranium kinetics and that a knowledge of the relevant diffusion coefficients will provide a rational basis for the design of ion exchange processes and plant equipment. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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