Thermoresponsive Ion-Imprinted Composite Hydrogels for Heavy Metal Ion Removal

摘要

A novel thermoresponsive Cu(II) ion-imprinted composite hydrogel [Cu(II)-IICH] based on N-isopropylacrylamide (NIPAM) and aminated silica (SiO2-NH2) has been prepared by in situ free-radical polymerization using Cu(II) ion as template. The Cu(II)-IICH was used to remove heavy metal ions from aqueous solution at 20 and 40oC. The Cu(II)-IICH selectively bound the template ion above a critical gel transition temperature (CGTT) of crosslinked poly(N-isopropylacrylamide) (PNIPAM). The memory was fixed by shrinking above the CGTT, and was deleted by swelling below the CGTT. In order to study the reusability of the Cu(II)-IICH, the sorption-desorption cycles were performed for five times. The results suggested that the Cu(II)-IICH can be used for several times without significantly decreasing its adsorption capacity.