## 3 Results and Discussion  
### Characterization of the CDM-HCP  
The CDM-HCP was obtained by the reaction of the swollen CM-PS with \(\beta\)-CD in DCE in the presence of anhydrous FeCl\({}_{3}\). SEM images of the CM-PS and CDM-HCP show that CM-PS has a smooth spherical surface. After being modified by \(\beta\)-CD, the CDM-HCP still retains spherical structure. However, its surface becomes rough and large crystalline particles of rather irregular size were observed on the surface of the CDM-HCP (Figure S1 (Supplementary Materials)). Figure 3 shows that the characteristic bands at 1270 and 670 cm\({}^{-1}\) are due to the C-Cl stretching vibration of the CM-PS's CH\({}_{2}\)Cl groups (Figure 3a) [31]. After the Friedel-Crafts alkylation reaction, the adsorption peak at 1270 cm\({}^{-1}\) is significantly weakened for HCP (Figure 3b). In addition, the CM-PS's chlorine content decreases from 18.01% to 4.32% (HCP). The results indicate that the CM-PS's C-Cl groups could be involved in the reaction and transformed to -CH\({}_{2}\)- groups. The results are in agreement with previous studies [32; 33]. The bands at 3380 and 1030 cm\({}^{-1}\) are due to -OH and C-O groups of \(\beta\)-CD [34] (Figure 3c). After the reaction of the HCP with \(\beta\)-CD, the band at 1030 cm\({}^{-1}\) appears in the CDM-HCP's FTIR spectrum, and the bands at 1270 and 670 cm\({}^{-1}\) nearly disappear, implying that the residual chlorine on the HCP's surface could be substituted by \(\beta\)-CD. In addition, the HCP's chlorine content further decreases to 0.24% and the adsorption band 3380 cm\({}^{-1}\) was increased by increasing the content of \(\beta\)-CD (Figure 3d), suggesting that \(\beta\)-CD exited in HCP [33]. In addition, Figure S2 (Supplementary Materials) shows the XPS wide scan of the HCP and CDM-HCP, respectively. In comparison with the HCP, the O\({}_{18}\) peak of the CDM-HCP was observed at 532.50 eV, whereas the Cl\({}_{2p}\) peak of the HCP nearly disappeared. For the C1s spectrum of the CDM-HCP in Figure S2 (Supplementary Materials), different valence states of carbon were present on the HCP's surface, and the peaks at 284.7 and 285.1 eV were due to the presence of C = C and C-O of \(\beta\)-CD, respectively, indicating the successful immobilization of \(\beta\)-CD in HCP [35]. Figure 2: Inclusion processes of \(\beta\)-CD with guests: (**a**) head down, (**b**) head up of \(\beta\)-CD with anilines for steps; (**c**) head down, (**d**) head up of \(\beta\)-CD with anilines for dihedral angles. Further analysis by TG (Figure S3 (Supplementary Materials)) showed that the CDM-HCP has good thermal stability with a thermal decomposition temperature of 375-400 \({}^{\circ}\)C due to its highly crosslinked network [36]. Such a high thermal stability is very conducive to adsorption and regeneration of the CDM-HCP in industrial applications. Figure 4 illustrates the N\({}_{2}\) adsorption-desorption isotherms and pore-size distribution for the CDM-HCP. The raw material CM-PS is nonporous when it is in a dry state, but it could produce macropores after swelling in DCE, making the -CH\({}_{2}\)Cl groups to be extended completely. It is attributed that they would have an electrophilic substitution with the neighboring benzene rings, inducing abundant rigid methylene crosslinking bridges, which would produce these macropores after drying (Figure 4a). The results indicate that the Friedel-Crafts reaction could result in higher BET surface area and pore volume. After adding \(\beta\)-CD to the reaction, the N\({}_{2}\) capacity decreases quickly, implying that the BET surface area decreases and some micropores mostly in the range of 20-50 nm exist in the CDM-HCP (Figure S2b and Table S1 (Supplementary Materials)). This result indicates that the HCP's surface pores are turned into micropores with the addition of functional groups [37]. Table S1 (Supplementary Materials) indicates that the O content of the CDM-HCP is 6.79%, which may be due to the introduction of \(\beta\)-CD, resulting in an increase in oxygen functional groups.