## 2 Results and Discussion  
### Synthesis and Characterization of MMIPs  
In this work, MMIPs were synthesized by suspension polymerization. A schematic of the MMIP preparation process is shown in Figure 1. First, superparamagnetic Fe\({}_{3}\)O\({}_{4}\) nanoparticles were prepared by a coprecipitation method. As these particles are hydrophilic, they cannot be effectively combined with functional monomers. Therefore, the Fe\({}_{3}\)O\({}_{4}\) particles were coated with oleic acid (OA) to modify the properties of the hydrophobic Fe\({}_{3}\)O\({}_{4}\) nanoparticles. Using glycidyl methacrylate (GMA) and methyl methacrylate (MMA) as functional monomers, divinylbenzene (DVB) as a cross-linker, poly(vinyl alcohol) (PVA) as a dispersant, and benzoyl peroxide (BPO) as an initiator, magnetic polymers containing epoxy groups were successfully synthesized. In the presence of ethylenediamine (EDA) and OFL, a ring-opening reaction occurred, and MMIPs with included template molecules were prepared. Finally, MMIPs with surface binding sites were achieved by removal of the templates.  
The morphological features of Fe\({}_{3}\)O\({}_{4}\) (a), OA-Fe\({}_{3}\)O\({}_{4}\) (b), and the MMIPs (c) were observed by TEM (Figure 2). These images revealed that the Fe\({}_{3}\)O\({}_{4}\) nanoparticles had irregular spherical shapes with diameters of about 20 nm. Some of the magnetic nanoparticles were aggregated with larger particles (Figure 2a). Following OA modification (Figure 2b), the dispersity of the particles improved and aggregation of the particles was significantly reduced. The presence of OA on the Fe\({}_{3}\)O\({}_{4}\) surface may have increased steric hindrance, thus preventing effective aggregation. The obtained MMIPs nanoparticles exhibited a well-defined core-shell configuration with a diameter of about 200 nm, as shown in Figure 2c. The grey areas are polymer layers, whereas the black areas are the cores, which contain many magnetic nanoparticles.  
The XRD patterns of Fe\({}_{3}\)O\({}_{4}\) (a) and the MMIPs (b) were obtained, as shown in Figure 3. Both XRD spectra show six peaks that are characteristic of Fe\({}_{3}\)O\({}_{4}\) at 2 \(\upmu\) = 30.4\({}^{\circ}\), 35.8\({}^{\circ}\), 43.3\({}^{\circ}\), 53.9\({}^{\circ}\), 57.3\({}^{\circ}\), and 63.1\({}^{\circ}\), which correspond to the (220), (311), (400), (422), (511), and (440) indices, respectively. This result reveals that the crystal structure of Fe\({}_{3}\)O\({}_{4}\) remained stable during the polymerization process  
Figure 4 shows the magnetic hysteresis loop analysis of Fe\({}_{3}\)O\({}_{4}\) (a) and the MMIPs (b). There was no apparent hysteresis in either curve, suggesting that Fe\({}_{3}\)O\({}_{4}\) and MMIPs were superparamagnetic. The saturation magnetization of Fe\({}_{3}\)O\({}_{4}\) and MMIPs was 69.733 and 13.046 emu g\({}^{-1}\), respectively. As shown in the inset photograph in Figure 4, the dispersed MMIPs were easily attracted to the wall of a vial under an external magnetic field. This result showed that MMIPs exhibit an adequate magnetic response to undergo magnetic separation.  
The FT-IR spectra of Fe\({}_{3}\)O\({}_{4}\) (a), OA-Fe\({}_{3}\)O\({}_{4}\) (b), and the MMIPs (c) are shown in Figure 5. The main functional groups of the predicted structures can be inferred from the infrared adsorption peaks. The adsorption peak at 580 cm\({}^{-1}\) in the spectra of Fe\({}_{3}\)O\({}_{4}\), OA-Fe\({}_{3}\)O\({}_{4}\), and the MMIPs corresponds to the Fe-O bond of Fe\({}_{3}\)O\({}_{4}\) particles. After OA modification (Figure 5b), new characteristic peaks located at 2854, 2923, 1425, and 1629 cm\({}^{-1}\) arose, which correspond to the stretching vibrations of -CH\({}_{3}\) and -CH\({}_{2}\)-, and the bending vibration of carboxylate. These peaks are consistent with successful coating of OA onto Fe\({}_{3}\)O\({}_{4}\). The new peak at 1567 cm\({}^{-1}\) observed for the MMIPs (Figure 5c) corresponds to the characteristic adsorption of -N-H, which indicates that the amino-functionalized MMIPs were successfully synthesized.