A novel dual temperature responsive mesoporous imprinted polymer for Cd(II) adsorption and temperature switchable controlled separation and regeneration

- A dual temperature responsive Cd(II) imprinted polymer (DT-IIP) was synthesized by photo-initiated RAFT polymerization.
- DT-IIP can be used to dual temperature switching controlled adsorption, separation and regeneration.
- The two LCST values of DT-IIP are responsible for the distinguished dual thermo-responsive behaviors.

A dual temperature responsive Cd(II) imprinted polymer (DT-IIP) was newly synthesized by taking merits of surface imprinted technology and photo-initiated controlled/living RAFT polymerization. The preparation, structure, properties as well as the temperature switching controlled behaviors and mechanism of DT-IIP were investigated in detail. SEM, TEM, FT-IR, TGA, XRD and N2 adsorption-desorption were applied to characterization, demonstrating that DT-IIP possesses dual temperature sensitive shells which account for thermo-responsive behaviors. The adsorption performances of DT-IIP towards Cd(II) were assessed by adsorption condition optimizing, the isotherm model, the kinetic model along with selectivity and recognition ability analysis. Moreover, the temperature switching controlled absorption, separation and regeneration of DT-IIP was simply performed, which stems from the two LCST values possessed, so that the distinguished thermo-responsive behaviors can be effectively controlled by single temperature factor. The structure changes of temperature sensitive shells in DT-IIP when exposed above or below LCST value are responsible for the temperature adjusting controlled behaviors. The reusability of DT-IIP was also appraised after temperature controlled adsorption, separation and regeneration sections, proved to be with splendid competence. This is the first time that dual temperature responsive imprinted polymers were effectively adapted to single temperature factor switching control of adsorption, separation and regeneration, which is of great value to sorbent recycling.