Th(IV) transport from nitrate media through hollow fiber renewal liquid membrane

A computational simulation of electromembrane extraction based on Poisson - Nernst - Planck equations

Electromembrane extraction (EME) has attracted a great deal of interest in researchers because of its advantages. For analysis, design and optimization purposes, understanding the ion transport mechanisms in the organic supported liquid membrane (SLM) is of prominent importance, where the interplay between the passive diffusion and electric-driven mass transport across SLM affects the mass transfer. In present work, a 2D numerical simulation is developed to examine the mass transfer behavior and the analyte recovery in EME devices. The presented model is capable of describing the effect of different parameters on the recovery of the EME setup. Initial analyte concentration in the sample solution, SLM thickness, applied potential, permittivity, diffusion coefficient, and the reservoir pH within both the sample and acceptor, can be considered as process variables. Predicted results revealed that the most important factors playing key role in EME, are the analyte diffusivity, distribution coefficient of the analyte as well as the level of protonation in both the donor and acceptor solutions. The proposed model is helpful in predicting the mass transfer behavior of the EME process in practical applications.

Performance evaluation of hollow fiber renewal liquid membrane for extraction of uranium(VI) from acidic sulfate solution

The performance of the hollow fiber renewal liquid membrane (HFRLM) in the continuous and recycling modes for the extraction of uranium(VI) from the acidic sulfate solution has been investigated. Alamine 336 diluted in kerosene was used as a carrier in liquid membrane (LM) phase. In the batch experiments, the effects of sulfuric acid, extractant and uranium(VI) concentration were studied and the optimum concentration of the donor and LM phases were determined 0.15 mol L−1and 0.0125 mol L−1, respectively. Various parameters affecting the HFRLM performance including the lumen and shell side flow rate, organic/aqueous volume ratio, acceptor phase type and concentration of carrier and acceptor phase were studied. The mass transfer flux increases with increasing the lumen side flow rates and the shell side flow rate did not have any significant effect. The uranium transfer flux increases with increasing O/A ratio, acceptor and Alamine 336 concentration, and reaches a maximum value at 1/20, 0.5 mol L−1and 0.0125 mol L−1, respectively. Further increase in these parameters result in uranium transfer decrement. The results show that liquid membrane phase is a rate-controlling step. Among the investigated acceptor phases, 0.5 mol L−1NH4Cl result in 60.35% uranium(VI) recovery in the recycling mode.

Th(iv) recovery from aqueous waste via hollow fiber renewal liquid membrane (HFRLM) in recycling mode: modelling and experimental validation

A new mathematical model was developed for recycling mode of HFRLM process which is in agreement with experimental results.