Facile synthesis of polypyrrole-functionalized CoFe 2 O 4 @SiO 2 for removal for Hg(II)

Abstract

In order to avoid using toxic or harmful operational conditions, shorten synthesis time, enhance adsorption capacity, and reduce operational cost, a novel magnetic nano-adsorbent of CoFe 2 O 4 @SiO 2 with core–shell structure was successfully functionalized with polypyrrole (Ppy). The physical and chemical properties of CoFe 2 O 4 @SiO 2 -Ppy are examined by various means. The as-prepared CoFe 2 O 4 @SiO 2 -Ppy nanomaterial was used to adsorb Hg 2+ from water. During the process, some key effect factors were studied. The adsorption process of Hg 2+ onto CoFe 2 O 4 @SiO 2 -Ppy was consistent with the pseudo-second-order kinetic and Langmuir models. The Langmuir capacity reached 680.2 mg/g, exceeding those of many adsorbents. The as-prepared material had excellent regeneration ability, dispersibility, and stability. The fitting of kinetics, isotherms, and thermodynamics indicated the removal was endothermic and spontaneous, and involved some chemical reactions. The application evaluation of electroplating wastewater also shows that CoFe 2 O 4 @SiO 2 -Ppy is an excellent adsorbent for Hg 2+ ions from water.