Efficient recovery of uranium from saline lake brine through photocatalytic reduction

There is abundant uranium resource in saline lakes, but extracting it for use is challenging due to the high salinity background. This study tested the application of the photocatalysis method for the efficient extraction of uranium from saline lake brine. The results showed that 50% of U(VI) was photocatalytically reduced in pure brine, while the extraction of U(VI) increased when brine was diluted with saline lake water. The photocatalytic extraction of U(VI) was restricted under acidic conditions, and ~100% of U(VI) could be recovered at pH ~5.5 from diluted brine. By applying the photocatalytic method, a high extraction capacity of 3010 mg/g could be achieved after 6 h UV irradiation, and the extracted uranium could be easily eluted by adding 0.1 M Na2CO3 after exposing to air for hours. During the photocatalytic reactions, U(VI) was reduced to U(IV), existing in the form of (UO2)O2·2H2O. In the practical application without spiked U(VI), 72 μg U(VI) could be recovered from 250 mL real brine, which was three times higher than the physicochemical adsorption. It is demonstrated that photocatalysis is a simple, green and efficient method for uranium extraction from saline lake water/brine.