Separation Science and Technology, Vol.48, No.5, 728-735, 2013
Carrier Mediated Transport of Thorium from Nitric Acid Medium using 2-Ethyl Hexyl Hydrogen 2-Ethyl Hexyl Phosphonate (PC88A)/N-Dodecane as Carrier
The present study deals with the application of supported liquid membrane (SLM) technique for the separation of thorium from nitric acid medium using 2-ethyl hexyl hydrogen 2-ethyl hexyl phosphonate (PC88A) as a carrier and aqueous ammonium carbonate as a receiving phase. The effects of feed acidity, nature of strippant, and membrane pore size and membrane thickness on the transport of thorium have been studied in detail. Transport behavior of uranium (233U) and fission products from a radioanalytical laboratory waste is also studied. Stability of the membrane against the leaching of the extractant and stability of the membrane support have been investigated. An attempt has been made to model the physicochemical transport of thorium in SLM and establish the mechanism of thorium transport. Transport of thorium increased from 25% to about 96% using 0.75M PC88A in n-dodecane as carrier and 2M ammonium carbonate as stripping phase as the feed acidity decreased from 4M HNO3 to 0.5M HNO3. Optimum conditions obtained from this study were applied to recover thorium and 233U from analytical waste generated in the laboratory.
Keywords:flux;PC88A;permeability coefficient;radioanalytical waste;supported liquid membrane;thorium transport