A thermal-responsive hydrogel to capture uranium(VI) from aqueous solution. Properties and mechanism

In this study, a thermal-responsive hydrogel, sodium alginate/polyamidoxime/poly(N-isopropylacrylamide) hydrogel (SA/PAO/PNIPAm), was prepared via radical polymerization. The uranium (U) capturing properties of the hydrogel were investigated. The results reveal that SA/PAO/PNIPAm can effectively remove U(VI) from aqueous solution, and the maximal adsorption capacity was calculated to be 319.49 mg g^-1 at 305.15 K and pH 5.0. Furthermore, the adsorption mechanism was revealed by X-ray photoelectron spectroscopy analysis and density functional theory simulations. In particular, high desorption efficiency was observed by changing the desorption temperature, which could reduce secondary pollutants in elution process. (author)