Facilitated transport of trivalent actinides (Am, Cm), lanthanides (La, Eu, and Lu) and fission product (Sr) was investigated from 1 M HNO₃ into 0.5 M α-hydroxy isobutyric acid (α-HIBA) through polymer inclusion membrane (PIM) consisting of cellulose triacetate (CTA) as a polymermatrix, 2-nitrophenyl n-octyl ether (NPOE)
as a plasticizer andN,N,N′,N′-tetraoctyl-3-oxapentanediamide (TODGA) as a carrier. The transport of Cm(III) was higher as compared to Am(III) which was ascribed to the higher ionic potential of the former. Effect of ionic potential was also demonstrated for lanthanides where the transport of Lu(III) wasmore as compared to La(III). The experimental results indicated that the transport ofmetal ions was controlled by the diffusion of the metal–ligand complex in the membrane phase.