Polysulfide grafted with hydrophilic group for efficient capture of uranium (VI) from water

• Hydrophilic polysulfide PS-HEA-X absorbents were synthesized by facile method. • The U(VI) adsorption capacity of hydrophilic PS-HEA-20 was 23 times higher than hydrophobic PS-HEA-0. • The U(VI) adsorption efficiency of PS-HEA-20 reached 124.42 mg/m 2 . • U(VI) was captured by surface S atoms through soft acids-soft base interaction. Efficient capture of uranium (VI) from wastewater holds great importance for environmental remediation and sustainable development of nuclear energy. Herein, polysulfide PS-HEA-X with grafted hydrophilic groups was fabricated as an efficient adsorbent for the capture of uranium (VI) in water by using 2-hydroxyethyl acrylate (HEA) as a hydrophilic regulator. The practical maximum uranium (VI) adsorption capacity of hydrophilic PS-HEA-20 reached 638.29 mg/g, which was about 24 times that of hydrophobic PS-HEA-0 synthesized without HEA modifier. The uranium (VI) adsorption capacity of PS-HEA-20 per unit surface area reached 124.42 mg/m 2 , which outperformed most reported absorbents. Structure-performance relations indicated that the grafted –OH, –COO- groups improved the hydrophilicity of PS-PEA-20, hereby facilitating the diffusion of uranium (VI) in solution to the surface of PS-PEA-20. Adsorption mechanism investigation results showed that UO 2 2+ were captured by the surface S atoms of PS-HEA-20 through soft acids-soft base interaction. PS-HEA-20 exhibited excellent reusability and the adsorption capacity remains higher than 90 % after five cycles using Na 2 CO 3 solution as eluent. This work not only expands the application of S-based polymer for efficient capture of uranium (VI) from water, but also offers a facile strategy for the fabrication of polysulfide for the capture of uranium (VI) and other heavy metal ions.