With proper modification, polyamidoxime (PAO) shows extraordinary solubility in aqueous alkaline solution. A hybrid sponge was prepared by freeze-drying an aqueous solution of PAO/alginate. After simple in situ ionic and covalent crosslinking, the sponge showed highly efficient uranium capture performance with a saturated adsorption capacity of 718.38 ± 12.38 mg g−1, as well as excellent chemical and mechanical stability in running seawater for weeks.
