Facile Synthesis of a Magnetic Glucose-Based Hyper-Cross-Linked Polymer by Dual-Role Ferric Chloride for Nitrophenol Removal from Sewage

Dual-purpose ferric chloride was successively used as a catalyst and iron source for ferric oxide to conveniently prepare a magnetic Fe3O4/HCPBn-glu polymer with tetrabenzylglucose as the precursor. First, ferric chloride was employed as a Friedel–Crafts reaction catalyst for the synthesis of hyper-cross-linked HCPBn-glu. Subsequently, the ferric chloride was utilized as an iron source for the synthesis of Fe3O4 magnetic nanoparticles by coprecipitation, which anchored Fe3O4 nanoparticles onto the HCPBn-glu skeleton. A variety of modern analytical techniques were used to characterize prepared Fe3O4/HCPBn-glu. The effects of adsorbent amount, contact time, and pH were studied, and this composite showed excellent adsorption performance for 2,4-dinitrophenol (DNP), with a maximum adsorption capacity of 83.3 mg/g and removal efficiency of 91.7%. The adsorption of DNP is well fitted by the Freundlich model, indicating multilayer adsorption. The adsorption kinetics obey a pseudo-second-order kinetic model. In addition, Fe3O4/HCPBn-glu can be reused for at least six cycles with an acceptable removal efficiency, making it an economically valuable adsorbent. The adsorption mechanism was also discussed, and hydrogen bond, hydrophobic, and π–π interactions may be responsible for DNP adsorption. Based on these results, Fe3O4/HCPBn-glu can be utilized as an effective adsorbent for the removal of nitrophenols from sewage.