Thermodynamics of extraction of Am(III) and Eu(III) from nitrate and thiocyanate media with octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide

Journal Article · Sun Nov 01 04:00:00 EST 1998 · Solvent Extraction and Ion Exchange

DOI:https://doi.org/10.1080/07366299808934583· OSTI ID:346981

Mathur, J N; Nash, K L ^[1]

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1. Argonne National Lab., IL (United States). Chemistry Div.

The extraction of Am(III) and Eu(III) from 1.0 M NH{sub 4}NO{sub 3} and NH{sub 4}SCN at pH 2.60 into octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) in n-dodecane has been studied in the temperature range 15.0 to 45.0 C. Under all conditions, the species ML{sub 3} {center_dot} 3 CMPO is the dominant extracted complex. The extraction equilibrium constants are at least 10{sup 3} higher in the SCN{sup {minus}} systems than in the NO{sub 3}{sup {minus}} systems. This difference is attributed to the relative energy associated with transfer of the anions from the aqueous to the extractant phase. Extraction enthalpies and entropies have been calculated in each system from the temperature dependence of K{sub ex}. Enthalpies are considerably more exothermic in the thiocyanate system for both metal ions. Comparison of {Delta}H{sub Am}{sup SCN} with {Delta}H{sub Eu}{sup SCN} gives a possible indication of enhanced Am-SCN bond strength in the extracted complex.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 346981
• Journal Information: Solvent Extraction and Ion Exchange, Journal Name: Solvent Extraction and Ion Exchange Journal Issue: 6 Vol. 16; ISSN 0736-6299; ISSN SEIEDB
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
AMERICIUM
CMPO
EUROPIUM
NITRATES
SOLVENT EXTRACTION
SORPTIVE PROPERTIES
THERMODYNAMIC PROPERTIES
THIOCYANATES