Separation of actinides using hollow fiber supported liquid membranes

Abstract

Hollow fiber supported liquid membrane (HFSLM) studies were carried out using TODGA (N,N,N′,N′-tetraoctyl diglycolamide) — DHOA (di-n-hexyloctanamide) — NPH (normal paraffin hydrocarbon) and Cyanex-301-n-dodecane as carriers. The first carrier was employed to recover trivalent actinides and lanthanides from simulated high level waste (SHLW) of pressurized heavy water reactor (PHWR) origin. Subsequently, the mutual separation of the actinides and the lanthanides was demonstrated with the second carrier (Cyanex-301-n-dodecane). Quantitative transport of Am(III) and Nd(III) was observed in 45 min from a feed solution (500 mL) containing 1 g/L Nd spiked with 241Am at 3 M HNO3. Similarly, all the lanthanides (La, Ce, Pr, Nd and Sm) and tracer Am(III) were quantitatively recovered in 30 min from SHLW. No significant transport of other metal ions present in SHLW was observed. Quantitative and selective recovery of Am(III) was achieved by Cyanex-301-n-dodecane from feed solution containing 1 g/L total lanthanides spiked with 241Am tracer. The physical stability of HFSLM was reasonably good during continuous operation for over 72 h. Radiolytic stability of solvent and hollow fibre module up to 500 kGy dose was also satisfactory.