Liquid–Liquid extraction of americium(III) using a completely incenerable ionic liquid system

Abstract

Americium(III) was extracted by a new CHNO based ionic liquid based extraction system. The extractant used was a diglycolamide, N,N,N′,N′-tetra(ethylhexyl)diglycolamide (T2EHDGA) and the diluent used was an incenerable ionic liquid, trioctylmethylammonium nitrate ([N1888][NO3]). The extraction of americium(III) using such type of ionic liquid as diluent is highlighted for the first time in this paper. The extraction behavior of americium(III) was investigated as a function of various parameters, such as aqueous phase acidity, extractant concentration, isomeric forms of the extractant and temperature. The extraction trend in T2EHDGA was compared with the other neutral extractant such as octylphenyl(N,N-diisobutylcarbamoylmethyl)-phosphinoxide (CMPO) and N,N-dimethyl-N,N-di-octyl-2-(2-hexyloxylethyl)malonamide (DMDOHEMA) in the ionic liquid, [N1888][NO3] and T2EHDGA was found to be superior as compared to the former two extractants. Changing the extractant type in to the isomeric form of T2EHDGA (N,N,N′,N′-tetraoctyl diglycolamide (TODDGA) and N,N-di(2-ethylhexyl)-N′,N′-dioctyldiglycolamide (DEHDODGA)) doesn’t exhibit any appreciable change in the extraction efficiency. Metal extraction was found to adopt neutral solvation pathway. Effect of thermodynamic parameters on the americium extraction was investigated in detail. The extracted americium(III) was stripped back from the ionic liquid phase using dilute nitric acid.