Novel diglycolamide-functionalized calix[4]arenes for actinide extraction and supported liquid membrane studies: Role of substituents in the pendent arms and mass transfer modeling

Diglycolamide-Functionalized Calix[4]arene for Am(III) Recovery from Radioactive Wastes: Liquid Membrane Studies Using a Hollow Fiber Contactor

“…The D mem value for the present system was calculated to be 5.01 × 10 –7 cm 2 /s. The D mem values obtained from the Wilke–Chang equation and those experimentally obtained by a lag-time experiment were 5.42 × 10 –6 and 1.93 × 10 –7 cm 2 /s, respectively, as reported in a previous report where PTFE flat sheets were used as the membrane support . The D mem values are in variance with those reported previously, which is due to the different polymeric material used in these studies and also to the difference in the porosity and tortuosity factors.…”

“…As shown in Figure , near quantitative Am­(III) transport was possible in <20 min at 300 mL feed scale. It is worth mentioning that under identical feed and receiver compositions in studies involving FSSLM (20 mL feed and receiver phase volumes), >4 h were needed for near quantitative Am­(III) transport . The higher transport efficiency in the present case is obviously due to the significantly large effective surface area (1800 cm 2 ) provided by the hollow fiber contactor as compared to the FSSLM (3.14 cm 2 ).…”

“…The species, Am­(NO 3 ) 3 · x E, represents the extracted complex in the membrane phase (or organic phase supported inside the pores of the membrane support). The term “ x ” is the number of C4DGA molecules present in the metal bearing complex, which has been confirmed to be 1 in the earlier solvent extraction studies . The two-phase extraction constant ( K ex ) for eq is given as …”

“…The equilibrium reaction between Am­(III) and the C4DGA ligand, taking place at the feed–membrane and the membrane–receiver interfaces, is described as follows: where, the term E stands for the extractant, C4DGA, while the species with the subscripts (aq) and (mem) indicate those present in the aqueous and the membrane phases, respectively. The species, Am­(NO 3 ) 3 · x E, represents the extracted complex in the membrane phase (or organic phase supported inside the pores of the membrane support).…”

“…Recently, we have demonstrated the feasibility of using the C4DGA ligand in FSSLM for the separation of Am­(III) from nitric acidic feeds . The study was performed at 20 mL scale with a 3.14 cm 2 membrane surface area, and the results were highly encouraging.…”