Preparation of Fe3O4@SiO2@ P(AANa-co-AM) Composites and Their Adsorption for Pb(II)

• Published in: ACS omega Vol. 5; no. 15; pp. 8816 - 8824
• Main Authors: Liu, Han, Wang, Qian, Zhang, Fan
• Format: Journal Article
• Language: English
• Published: American Chemical Society 21.04.2020
• ISSN: 2470-1343; 2470-1343
• DOI: 10.1021/acsomega.0c00403

A series of magnetic composites of sodium polyacrylate and polyacrylamide copolymer [Fe3O4@SiO2@P­(AANa-co-AM)] were prepared. The investigation showed that the adsorption efficiency of Pb­(II) was the best when the acrylamide/acrylic acid (AM/AA) mass ratio of composites was 5:5. Therefore, the composite of this ratio was selected as the adsorbent to systematically adsorb Pb­(II) in aqueous solution. Static adsorption of Pb­(II) to the magnetic composites in aqueous solutions was investigated by varying the solution pH and the concentration of Pb­(II). The adsorption kinetics and isotherms model of Pb­(II) on the Fe3O4@SiO2@P­(AANa-co-AM) composites followed a pseudo-second-order model and the Langmuir isotherm model, respectively. When the temperatures were 298.15, 308.15, and 318.15 K, the maximum adsorption capacities of Fe3O4@SiO2@P­(AANa-co-AM) composites were 237.53, 248.14, and 255.10 mg/g, respectively. The thermodynamic study of adsorption showed that the adsorption of Pb­(II) on Fe3O4@SiO2@P­(AANa-co-AM) composites was a spontaneous endothermic process. The X-ray photoelectron spectroscopy (XPS) analysis showed that the adsorption of Pb­(II) was due to the chelation between −COO– and Pb­(II). After four adsorption–desorption cycles, the adsorbent can still maintain a high adsorption capacity.