Facile fabrication of highly efficient bifunctional polydopamine–polyethyleneimine copolymerization‐modified magnetic material and its effective applications for both adsorption of gold ions and catalytic reduction of 4‐nitrophenol

Abstract The heavy metal ions and organic pollutants are major harmful substances in wastewater because of their toxicity on human health and environment. Nowadays, the adsorption–catalysis treatment to remove them simultaneously is still a challenge because of their different reaction mechanisms. Herein, a novel bifunctional polymer magnetic material Fe 3 O 4 @PDA‐PEI was successfully developed through a facile co‐deposition method by the copolymerization modification of polydopamine (PDA) and polyethyleneimine (PEI) on magnetic ferroferric oxide, which can both be utilized for both heavy metal ion removal from simulated industrial wastewater and further effective catalytic reduction of toxic 4‐nitrophenol (4‐NP) to useful 4‐aminophenol. The maximum adsorption capacity of Fe 3 O 4 @PDA‐PEI for gold ions was 465.12 mg/g at 35°C, and the adsorption thermodynamic parameters Δ G , Δ H , and Δ S of Fe 3 O 4 @PDA‐PEI (m(PDA):m(PEI) = 2:1) were −5.28 (35°C), 25.58, and 111.30 J K −1 mol −1 , respectively. In addition, a sustainable strategy of converting gold ions to gold nanoparticles has been demonstrated for additional catalytic functionality of Fe 3 O 4 @PDA‐PEI, and Fe 3 O 4 @PDA‐PEI‐Au could effectively catalyze the reduction of 4‐NP at ambient temperature within 9 min. Fe 3 O 4 @PDA‐PEI with the advantages of facile fabrication, easy separation, excellent adsorption, and catalysis performance could be used as a promising polymer composite material in complicated wastewater environment. © 2023 Wiley Periodicals LLC.