A new imidazolium-based polymeric ionic liquid gel with high adsorption capacity for perrhenate

A new imidazolium-based polymeric ionic liquid (PC2vimBr) gel was prepared by γ-radiation induced polymerization and crosslinking of 1-vinyl-3-ethylimidazolium bromide and a functional crosslinker 3,3′-divinyl-1,1′(1,6-hexanediyl) diimidazolium dibromide. A high gel fraction of ca. 95% could be achieved under 40 kGy, and the equilibrium degree of swelling and mechanical properties could be adjusted by crosslinker content and absorbed dose. The highest fracture compressive strength of PC2vimBr could be as high as 0.21 MPa. PC2vimBr could strongly adsorb perrhenate (ReO4−) with an adsorption capacity as high as ca. 8.6 × 102 mg g−1 (Re/gel), following a Langmuir model by an ion exchange mechanism, which was confirmed by IR and XPS. Competitive adsorption with the electrolytes or sodium dodecyl benzene sulfonate showed that the PC2vimBr gel has good efficiency for ReO4− removal from a low concentration of electrolyte solution or laundry waste water. Considering ReO4− is the natural analogue of TcO4−, PC2vimBr may be used in decontamination of low level wastes such as laundry wastes. Interestingly, PC2vimBr would shrink strongly after adsorbing ReO4−, which is meaningful for volume reduction of radioactive wastes.