An ion-imprinted polymer based on palygorskite as a sacrificial support for selective removal of strontium(II)

Surface ion-imprinting technique combined with a sacrificial-support process was established to synthesize Sr(II) ion imprinted polymer (S-IIP) palygorskite which acted as the sacrificial support. FT-IR, TEM, nitrogen gas adsorption and laser particle size measurements were employed for the characterization of S-IIP and non-imprinted polymer (NIP). Factors for the adsorption of Sr(II) ions were investigated. Under the optimum condition, adsorption and selective recognition of Sr(II) ions followed the order S-IIP>NIP. The adsorption equilibrium data were fitted by the Langmuir isotherm model and the monolayer adsorption capacity of S-IIP was 45.0mg g^-1 at 298K, 53.5mg g^-1 at 308K and 58.5mg g^-1 at 318K. Adsorption was described by the pseudo-second-order kinetics, and the thermodynamic parameters also indicated that the adsorption process was spontaneous but endothermic. S-IIP was a promising adsorbent for the selective removal of traces of Sr(II) ions. It could be reused four times with only about 5% loss for adsorption and 17% loss for desorption.