Recovery of Actinides and Lanthanides from High-Level Waste Using Hollow-Fiber Supported Liquid Membrane with TODGA as the Carrier

Transport behavior of trivalent actinides/lanthanides from nitric acid solutions into distilled water was investigated using polypropylene hollow-fiber supported liquid membrane (HFSLM) technique. A mixture of 0.1 M TODGA (N,N,N′,N′-tetraoctyl diglycolamide) + 0.5 M DHOA (N,N-dihexyl octanamide) dissolved in normal paraffinic hydrocarbon (NPH) was optimized as a suitable carrier. The permeability of the transported metal species was calculated with the help of various diffusional parameters. The permeation of metal ions increased with the feed acidity; however, their transport rates were significantly affected at higher acidity (>3 M HNO3) owing to carrier-aided co-transport of nitric acid. Mass transfer coefficients were calculated on the basis of the described model, whose success was verified by excellent matching of the membrane diffusion coefficient values calculated by the given model and Wilke−Chang equation. Quantitative transport of trivalent actinides and lanthanides was achieved in 30 min from ...