Figure 3.

pH dependence, selectivity, and recycle properties of the PAO hydrogel (m _AAM:m _PAO = 4:4) membrane for uranium extraction. a) The uranium adsorption efficiency of PAO hydrogel in 32 ppm uranium‐spiked ultrapure water solutions with different pH value. b) Adsorption selectivity of PAO hydrogel on the uranyl ion and other metal ions in a simulated seawater (U, V, Cu, Fe, Ni, Zn are as 100 times as the natural seawater; Na, Ca, Mg, K are equal to the natural seawater). c) The uranium adsorption capacities (blue columns) and recovery rates of elution (red columns) in five adsorption–desorption cycles (elution solution of 1.0 m Na₂CO₃ and 0.1 m H₂O₂). d) The flow‐through uranium extraction system containing 12 parallel adsorption beds with 1.0 T of natural seawater. e) U‐adsorption performance of the PAO hydrogel membrane (m _AAM:m _PAO = 4:4) from natural seawater during four weeks by the flow‐through uranium extraction system. (All scale bars in photos are 1.0 cm.)