Self-assembled porous polydopamine microspheres modified polyacrylonitrile fiber for synergistically enhanced U(VI) extraction and seawater desalination

The scarcity of water and energy is one of the main challenges on human development. Here, polydopamine porous microspheres were grown in situ on the surface of cyclized polyacrylonitrile amidoxime fibers by single micelle self-assembly to synthesize cyclized polyacrylonitrile amidoxime fiber-based polydopamine (CPAO/PDA-2). CPAO/PDA-2 exhibits high adsorption performance and selectivity for uranium (U), stability, and excellent evaporation rate. The photothermal temperature maintains as high as 104.2 ± 1.6 °C under sunlight, which accelerates the thermal motion of molecules around the material, increases the adsorption rate and prevents the adhesion of all biofouling. CPAO/PDA-2 exhibits U(VI) adsorption capacity of 4.4 mg g⁻¹ and an evaporation rate of 2.7 kg m⁻²h⁻¹ in natural seawater due to the photoinduced effect. The three-dimensional porous CPAO/PDA-2 provides sufficient water transport and increases the binding sites of uranyl ions. CPAO/PDA-2 shows enhanced adsorption capacity and superior evaporative water efficiency, and reconciles the relationship between fresh water and nuclear energy, providing a solution to the growing human needs.