Magnetic dummy-template molecularly imprinted polymer with an ultrathin shell for selective enrichment of geosmin in water sample

A dummy-template molecularly imprinted polymer (DMIP) based on magnetic carbon nanotubes was synthesized. The eluted polymers with an improved ultrasound assisted/oscillating (magnetic separation) method were successfully employed for the adsorption and separation of geosmin (GSM), an odorous compound in eutrophic waterbodies. The properties of the obtained composite materials were evaluated through a series of morphological and physicochemical characterization. The results showed that a thin and uniform imprinted shell (∼10–15 nm) effectively coated the surface of magnetic carbon nanotubes, exhibiting good adsorption efficiency and magnetic functionality. The binding performance and selectivity of Mag-MWCNTs @DMIPs as adsorbents for GSM were evaluated and compared with non-imprinted polymers. The maximum adsorption capacity of polymers for GSM, as determined by the Langmuir model, is 18.71 mg g−1, which adsorption equilibrium reached in approximately 45 min. The adsorption thermodynamic parameters ΔG shown that the adsorption process was spontaneous. Selectivity and regeneration experiment further demonstrated the ability of Mag-MWCNTs @DMIPs to selectively separate trace GSM from complex matrices. The polymer obtained in this study can be used as an adsorbent for magnetic dispersion solid-phase extraction to preconcentration of trace GSM in natural water, facilitating the measurement of GSM.