Preparation and recycled simultaneous adsorption of methylene blue and Cu2+ co-pollutants over carbon layer encapsulated Fe3O4 /graphene oxide nanocomposites rich in amino and thiol groups

Abstract

To find an efficient material to simultaneously remove the co-existed ionic dyes and toxic metal ions, in this paper, carbon layer encapsulated Fe 3 O 4 /graphene oxide nanocomposites rich in amino and thiol groups (Fe 3 O 4 @C /GO) was fabricated. With methylene blue (MB) and Cu 2+ as two different models of pollutants, the effects of time, initial concentration, pH values, and adsorbent dosage on the adsorption capacity of GO/ Fe 3 O 4 @C were conducted, respectively. A pseudo-second order rate model best simulated the kinetic adsorption process for both MB and Cu 2+ among the pseudo-first order, pseudo-second order, and Weber and Morris intra-particle diffusion models. The adsorption data were better fitted with the Langmuir adsorption isotherm model than Freundlich equation for both MB and Cu 2+ adsorption. The monolayer adsorption capacities analyzed from Langmuir model were 116.50 mg . g −1 and 76.86 mg . g −1 for MB and Cu 2+ , respectively. In MB- Cu 2+ binary system, resulted from the smaller separation factor (S F ) value of MB than Cu 2+ , MB had a suppression effect on Cu 2+ ions binding during the simultaneous adsorption process. But for the MB simultaneous adsorption and preloading, the impact of Cu 2+ ions on the MB adsorption capacity was almost negligible. Besides these important results, the easily magnetically separation and good regeneration property of Fe 3 O 4 @C /GO further indicated a kind of stable and efficient adsorbent with great potential in sewage treatment, while being very adaptable when compared with other magnetic carbon-based adsorbents. To find an efficient material to simultaneously remove the co-existed ionic dyes and toxic metal ions, carbon layer encapsulated Fe 3 O 4 /graphene oxide nanocomposites rich in amino and thiol groups were designed and synthesized as an adsorbent for recycled simultaneous removal of methylene blue (MB) and Cu 2+ co-pollutants, as well as the studies on parameters affecting adsorption capacity, kinetic, thermodynamic and mechanisms analysis. • Fe 3 O 4 @C /graphene oxide nanocomposites with amino/thiol-rich groups were fabricated. • The nanocomposites can simultaneously remove MB and Cu 2+ with a high efficiency. • Equilibrium data were well fitted by the Langmuir model for both MB and Cu 2+ . • A pseudo-second order rate model best simulated the kinetic adsorption process. • Suppression adsorption for Cu 2+ by MB was observed in the simultaneous adsorption process.