Abstract
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•MPILs with high theory adsorption for anionic pollutants removal were designed.•PDVIm-Cl-SCD shows high adsorption capacity of 328.2 mg g−1 to Cr(VI) at 25 °C.•PDVIm-Cl-SCD displays unprecedented adsorption capacity of 1615.0 mg g−1 to MO at 25 °C.•Much less volume of solution was used for regenerating the Cr(VI) and MO saturated columns.
Poly(ionic liquid)s (PILs) are attractive for their various applications, but the use of porous PILs have rarely been reported in anionic pollutants removal via ion-exchange by column. Herein, we report a serial of crosslinked imidazolium-based mesoporous PILs with Cl− and Br− as anions for hexavalent chromium (Cr(VI)) and methyl orange (MO) removal. Among them, PDVIm-Cl-SCD, from the free-radical polymerization of a dicationic monomer (N,N'-methylene-bis(1-(3-vinylimidazolium)) chloride, DVIm-Cl) and further supercritical carbon dioxide drying (SCD), displayed a very high sorption capacity (328.2 mg g−1 at 25 °C) and excellent utilization of adsorption sites (UOA, 86.2%) towards Cr(VI), and an unprecedentedly high sorption capacity (1615.0 mg g−1 at 25 °C) with a UOA of 67.4% to MO. Moreover, PDVIm-Cl-SCD also exhibited a broad pH range, excellent regeneration and remarkable reusability. Regarding to Cr(VI) removal, the volume of saturated KCl aqueous used for regenerating the Cr(VI) saturated PDVIm-Cl-SCD column (7.5–9.5 mL) was much less than the volume of treated Cr(VI) solution (160–200 mL). For MO removal, the volume of saturated NaCl solution used for regenerating the MO saturated PDVIm-Cl-SCD column (10.5–13.5 mL) was also much less than the volume of treated MO solution (220–235 mL), implying the great potential of PDVIm-Cl-SCD in sustainable wastewater treatment.