Extraction of Cu2+ from aqueous solutions using microcapsules containing ionic liquid [BMIM]PF6

Abstract

Polysulfone (PSF) microcapsules filled with ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF₆] were successfully prepared via solvent evaporation method. The encapsulation capacity of 38.0% was achieved. Microcapsules showed a spherical, porous honeycomb structure. The size of microcapsules was approximately 110 μm and the thickness was approximately 10 μm. Microcapsules have excellent thermal stability, with a higher thermal degradation onset temperature of 360°C compared to traditional extractant-loaded microcapsules. Microcapsules were used to extract Cu²⁺ from aqueous solutions. The effect of chelator, pH, PSF, and ionic liquid on the extraction rate were studied. When chelator was added in aqueous solutions, and the pH of aqueous solutions was 4.5, the extraction rate of microcapsules reached the maximum value, which was 99.0%. These PSF microcapsules containing [BMIM][PF₆] showed potential ability in the treatment of wastewater.