Transport of Americium(Ⅲ) through a supported liquid membrane containing N,N,N',N'-tetraoctyl-3-oxapentane diamide (TODGA) in n-dodecane as the carrier

摘要

The facilitated transport of Am(Ⅲ) from aqueous nitrate solutions through a supported liquid membrane (SLM) made from N,N,N',N'-tetraoctyl-3-oxapentane diamide (TODGA) in n-dodecane as the carrier inside microporous PTFE membranes of 0.45 μm pore size was investigated from an aqueous feed containing nitric acid. The transport mechanism consists of a diffusion process through an aqueous diffusion film, a fast interfacial chemical reaction, and diffusion through the membrane itself. The transport rates were correlated with the carrier concentration, feed nitrate concentration as well as the feed acidity. The effect of various strippant solutions on the transport of Am(Ⅲ) was also investigated. The transport of feed acid to the receiver phase was increased with the feed acidity which influenced the transport rate of the metal ion at higher acidity ( > 2 M HNO_3). Maximum transport was observed with a carrier concentration of 0.1 M and a feed acidity of 2M HNO_3. The membrane stability was remarkably good when tested over 20 days of continuous operation.