Transport of Tm(III) through dispersion supported liquid membrane containing PC-88A in kerosene as the carrier

Abstract

The transport of Tm(III) through a dispersion supported liquid membrane (DSLM) consisting of polyvinylidene fluoride membrane (PVDF) as the liquid membrane support and dispersion solution concluding HCl solution as the stripping solution and 2-ethyl hexyl phosphonic acid-mono-2-ethyl hexyl ester (PC-88A) dissolved in kerosene as the membrane solution, has been studied. The effects of pH value, initial concentration of Tm(III) and different ionic strength in the feed phase, volume ratio of membrane solution and stripping solution, concentration of HCl solution, concentration of carrier, different stripping agents in the dispersion phase on transport of Tm(III) have also been investigated, respectively. As a result, the optimum transport condition of Tm(III) was that concentration of HCl solution was 4.0 mol/L, concentration of PC-88A was 0.16 mol/L, and volume ratio of membrane solution and stripping solution was 40:20 in the dispersion phase, and pH value was 5.1 in the feed phase. Ionic strength had no obvious effect on transport of Tm(III). Under the optimum condition studied, when initial concentration of Tm(III) was 1.0 × 10 −4 mol/L, the transport percentage of Tm(III) was up to 92.2% during the transport time of 155 min. The kinetic equation was developed in terms of the law of mass diffusion and the theory of interface chemistry. The diffusion coefficient of Tm(III) in the membrane and the thickness of diffusion layer between feed phase and membrane phase can be obtained to 4.42 × 10 −8 and 17.99 μm, respectively. The results obtained were in good agreement with the literature data.