Magnetic molecularly imprinted microspheres via yeast stabilized Pickering emulsion polymerization for selective recognition of λ-cyhalothrin

In our study, magnetic molecularly imprinted microspheres (MMIMs) were prepared via Pickering emulsion polymerization. The template λ-cyhalothrin (LC), functional monomers and hydrophobic Fe 3 O 4 nanoparticles, served as magnetic carrier, were contained in oil phase. Modified yeast dispersed in water phase was employed as stabilizer to establish stable oil-in-water Pickering emulsion, and the imprinting process was conducted by thermally initiated radical polymerization of functional and cross-linked monomers. Characterization results indicated that the Pickering emulsion and MMIMs were successfully produced. The MMIMs possessed thermal stability (below 200   °C), magnetic sensitivity ( M s   =   0.73   emu   g −1 ) and magnetic stability (over the pH range of 2.0–8.0). Then, the MMIMs were used as sorbents for the selective recognition of LC. The Langmuir isotherm model gave a better fit to the experimental data, indicating the monolayer molecular adsorption for LC. The adsorption kinetic data was well described by the pseudo-second-order kinetics model, suggesting that the chemical process could be the rate-limiting step in the adsorption of LC. The selectivity study displayed the excellent selective recognition for LC compared to structural analog and non-analog in unitary and binary solutions. Furthermore, the satisfying regeneration capability of the sorbents was proved by at least three repeated adsorption–desorption cycles.