Application of supported liquid membranes for removal of nitrate, technetium (VII) and chromium (VI) from groundwater
| Autor: | R. Chiarizia |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Facilitated diffusion
Chromate conversion coating Chemistry Potentiometric titration Inorganic chemistry Filtration and Separation Amberlite Biochemistry Glass electrode law.invention chemistry.chemical_compound Membrane law Liquid–liquid extraction Nitric acid General Materials Science Physical and Theoretical Chemistry |
| Zdroj: | Journal of Membrane Science. 55:39-64 |
| ISSN: | 0376-7388 |
| DOI: | 10.1016/s0376-7388(00)82326-1 |
| Popis: | The separation of nitrate, pertechnetate and chromate ions from synthetic Hanford site groundwater was studied by liquid-liquid extraction and by supported liquid membranes, SLMs. Three different commercially available long-chain aliphatic amines, Primene JM-T (primary), Amberlite LA-2 (secondary) and trilaurylamine (TLA, tertiary), were investigated as membrane carriers, n-Dodecane was used as diluent and polypropylene membranes were used as the support. Sodium hydroxide was used as the stripping agent. The basic strength of the three amines in dodecane was studied by biphasic potentiometric titrations using a glass electrode. Flat-sheet membrane experiments, where the removal of nitric acid from the feed solution was followed by using either a glass electrode or a nitrate electrode, showed that the secondary and primary amines are more effective than the tertiary one. A detailed study of the permeation of nitric acid through SLMs as function of the concentration of the three amines in the liquid membrane was performed. Information was obtained on the diffusion coefficients of nitric acid in the aqueous phase and of the nitrate-alkylammonium salt in the membrane phase. A similar investigation was performed with HTcO 4 . In this case the secondary and tertiary amines proved to be better carriers. The secondary amine also performed better than the other two as a carrier for H 2 CrO 4 . The primary amine showed the unique feature of removing U (VI) as an anionic sulfato-complex, together with nitrate, pertechnetate and chromate ions, from the synthetic groundwater. |
| Databáze: | OpenAIRE |
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