Extraction of Re(VII) from hydrochloric acid medium by N263/TBP/n-heptane/NaCl microemulsion

In the present work, the extraction of Re(VII) from hydrochloric acid solution by N263/TBP/n-heptane/NaCl microemulsion was studied. In the extraction system, methyl trioctylammonium chloride (N263) bears double functions as a surfactant and an extractant. The extraction mechanism of Re(VII) by N263/TBP/n-heptane/NaCl was anion-exchange and complexation, and the extracted species could be referred as R3CH3N+ ReO4− and (R3CH3N+ Cl−)∙(NH4ReO4) with a ratio of 1:3. A more detailed characterization of the microemulsion droplets was analyzed by mean of conductivity measurement, and the interactions in organic phase were deduced by Fourier transform infrared (FTIR) spectroscopy analysis. Further, the average dynamic radii of the nanodroplets in the organic phase were determined with the dynamic light scattering (DLS) method. Moreover, Re(VII) could be selectively extracted (E% > 90%) when the ratio of Re(VII) to Mo(VI) was 2:5, 1:5, 1:10 and 1:20 (20 mg L− 1 of Re(VII)), respectively. Therefore, the extraction of Re(VII) from molybdenum solutions by microemulsion was an effective approach with high selectivity.