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The United States of America As Represented by the United States

The United States of America As Represented by the Department of Energy

Lockheed Martin Energy Research Corporation

Richard A Sachleben

Bruce A Moyer

Peter V Bonnesen

Robert S Foote

Derek J Presley

Fluoro-alcohol phase modifiers and process for cesium solvent extraction

A solvent composition and corresponding method for extracting cesium (Cs) from aqueous neutral and alkaline solutions containing Cs and perhaps other competing metal ions is described. The method entails contacting an aqueous Cs-containing solution with a solvent consisting of a specific class of lipophilic calix&lsqb;4&rsqb;arene-crown ether extractants dissolved in a hydrocarbon-based diluent containing a specific class of alkyl-aromatic ether alcohols as modifiers. The cesium values are subsequently recovered from the extractant, and the solvent subsequently recycled, by contacting the Cs-containing organic solution with an aqueous stripping solution. This combined extraction and stripping method is especially useful as a process for removal of the radionuclide cesium-137 from highly alkaline waste solutions which are also very concentrated in sodium and potassium. No pre-treatment of the waste solution is necessary, and the cesium can be recovered using a safe and inexpensive stripping process using water, dilute (millimolar) acid solutions, or dilute (millimolar) salt solutions. An important application for this invention would be treatment of alkaline nuclear tank wastes. Alternatively, the invention could be applied to decontamination of acidic reprocessing wastes containing cesium-137.

Calixarene crown ether solvent composition and use thereof for extraction of cesium from alkaline waste solutions

Nucleosides with photolabile protecting groups on the 5'-hydroxyl. These nucleosides are useful in the sythesis of nucleic acids on solid-state arrays.

Nucleosides with 5'-O-photolabile protecting groups

A process for extracting technetium values from an aqueous alkaline solution containing at least one alkali metal hydroxide and at least one alkali metal nitrate, the at least one alkali metal nitrate having a concentration of from about 0.1 to 6 molar. The solution is contacted with a solvent consisting of a crown ether in a diluent for a period of time sufficient to selectively extract the technetium values from the aqueous alkaline solution. The solvent containing the technetium values is separated from the aqueous alkaline solution and the technetium values are stripped from the solvent.

Process for extracting technetium from alkaline solutions

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Westford, MA, United States of America

Richard A Sachleben