Sol-gel transition effect based on konjac glucomannan thermosensitive hydrogel for photo-assisted uranium extraction.

Inspired by the intelligent gel phase transition effect, we applied temperature-responsive γ-FeOOH/KGM(Ga)/PNIPAM hydrogel with reversible sol-gel transition for uranium enrichment and separation in carbonate-containing wastewater. In carbonate-containing wastewater, the hydrogel achieved a high uranium removal rate of 92.3%, exceeding 90% even in actual uranium mine wastewater. Additionally, the adsorption-reduction-nucleation-crystallization mechanism of uranium on the temperature-responsive hydrogel was revealed using multi-spectral coupling techniques. [Display omitted] Exploiting the intelligent photocatalysts capable of phase separation provides a promising solution to the removal of uranium, which is expected to solve the difficulty in separation and the poor selectivity of traditional photocatalysts in carbonate-containing uranium wastewater. In this paper, the γ-FeOOH/konjac glucomannan grafted with phenolic hydroxyl groups/poly- N -isopropylacrylamide (γ-FeOOH/KGM(Ga)/PNIPAM) thermosensitive hydrogel is proposed as the photocatalysts for extracting uranium from carbonate-containing uranium wastewater. The dynamic phase transformation is demonstrated to confirm the arbitrary transition of γ-FeOOH/KGM(Ga)/PNIPAM thermosensitive hydrogel from a dispersed state with a high specific surface area at low temperatures to a stable aggregated state at high temperatures. Notably, the γ-FeOOH/KGM(Ga)/PNIPAM thermosensitive hydrogel achieves a remarkably high rate of 92.3% in the removal of uranium from the wastewater containing carbonates and maintains the efficiency of uranium removal from uranium mine wastewater at over 90%. Relying on electron spin resonance and free radical capture experiment, we reveal the adsorption-reduction-nucleation-crystallization mechanism of uranium on γ-FeOOH/KGM(Ga)/PNIPAM thermosensitive hydrogel. Overall, this strategy provides a promising solution to treating uranium-contaminated wastewater, showing a massive potential in water purification. [ABSTRACT FROM AUTHOR]