Modeling of gadolinium recovery from nitrate medium with 8-hydroxyquinoline by emulsion liquid membrane.
The extraction equilibrium of Gd(III) from nitrate medium by 8-hydroxyquinoline (HOX) in toluene was studied. Liquid-liquid investigations were first carried out. Based on the equilibrium results, the extraction of Gd(III) from aqueous nitrate medium into an emulsion liquid membrane system (ELM) containing 8-hydroxyquinoline in toluene as extractant, HNO(3) as stripping solution, Span-80 as surfactant was studied. The stability of the prepared ELM was studied in terms of the degree of membrane breakage. The different parameters affecting the permeation of gadolinium (III) were also studied. A general permeation model for the recovery of Gd(III) by the selected membrane is presented. The internal mass transfer in the water in oil (W/O) emulsion drop, the external mass transfer around the drop, the rates of formation and decomposition of the complex at the external aqueous-organic interface were considered.
Recovery of uranium from thorium in hydrochloric acid medium by liquid emulsion membranes containing trioctylphosphine oxide
The isolation of minor uranium concentration from thorium matrix in HCl medium was investigated using liquid emulsion membrane (LEM) containing TOPO as carrier, Span 80 as surfactant and sodium citrate as stripping agent. The factors affecting the stability of the LEM were investigated. Different parameters affecting the permeation process were also studied. The results obtained showed that, under certain conditions it is possible to isolate ca. 98% of U(VI) (120 ppm) in 1.0M HCl solution containing Th (1000 ppm). The isolated U was found to be contaminated with less than 3% of Th.
EXTRACTION OF AMINE BY W/O/W EMULSION SYSTEM
A mass transfer model for the extraction of amine in W/O/W emulsion systems having internal aqueous HCl solution phase is presented which takes into account the diffusion in W/O emulsion drops as well as the external mass transfer around W/O emulsion drops, and the effect of various parameters on the extraction rate is clarified. Experimental data on the extraction of aniline, p-and m-toluidine by W/O/W emulsion systems using a batch-type agitation vessel is discussed on the basis of the present model. It is found that the model can explain the tendency of the experimental data. The mass transfer mechanism in W/O emulsion drops is discussed on the basis of the experimentally evaluated value of effective diffusivity in W/O emulsion drops.