This research studied the separation of mixture of tantalum and niobium ions from synthetic feed via hollow fiber supported liquid membrane. The feed and stripping solutions were fed counter-currently at equal flow rate of 100 ml/min. The extractants or carrier were TBP and Aliquat 336. Other parameters were studied: concentration of hydrofluoric in feed solution, concentration of the carrier in the membrane phase, types of stripping solutions and their concentration, and initial concentration of tantalum and niobium ions in feed solution. From the experimental results, tantalum ions of about 78% could be selectively extracted by 3% (v/v) Aliquat 336 with 0.3 M hydrofluoric in feed solution. The highest percentage of stripping of tantalum ions about 67% could be retrieved by 0.2 M NaClO₄. The increasing of tantalum and niobium ions concentration in the feed solution in the range of 10-90 ppm showed no effect on the percentages of extraction and stripping. The mass transfer coefficient of tantalum ions in the aqueous feed (k [subscript i]) and that of complex ions in the organic membrane phase (k [subscript m]) were estimated as 1.19 × 10⁻⁵ and 1.44 × 10⁻⁷ cm/s, respectively. It is indicated that the mass transfer controlling step is the diffusion of the complex ions of tantalum and Aliquat 336 across the liquid membrane. Furthermore, in this paper a mass-transfer modeling was used to calculate the concentration of tantalum ions with time to estimate the separation time. The model was validated as the theoretical values from the model were found to be in good agreement with the experimental data, particularly at the concentration of Aliquat 336 in the membrane phase less than 4% (v/v).
