Thermosensitive/magnetic molecularly imprinted polymers prepared by Pickering emulsion polymerization for selective separation of bifenthrin

Thermosensitive/magnetic molecularly imprinted polymers (TM-MIPs) were prepared by Pickering emulsion polymerization. With this method, SiO₂ nanoparticles were used as the Pickering emulsion stabilizer, N-isopropylacrylamide functioned as the thermosensitive monomer participating in co-polymerization, and bifenthrin (BF) acted as the template molecule. The results of the characterizations demonstrated that the TM-MIPs were porous and magnetic inorganic/polymer composite microparticles with magnetic sensitivity (M_s = 0.7921 emu g⁻¹), thermal stability (below 473 K), and magnetic stability (over the pH range of 2.0–8.0). TM-MIPs were used as sorbents to remove bifenthrin (BF), and then were swiftly split in magnetic field. The Freundlich isotherm model preferably matched with the experimental data. The adsorption kinetic of the TM-MIPs was primely fitted by the pseudo-second-order, indicating that the chemical reaction could be the rate-limiting step in the process of BF absorption. The selective recognition experiments exhibited that the TM-MIPs have obvious effect on selective adsorption of BF with diethyl phthalate and fenvalerate. In aqueous solutions, the adsorption of BF onto the TM-MIPs had response to temperature, and could be used for adsorbing and separating bifenthrin.