Recyclable Fe3O4@C nanocomposite as potential adsorbent for a wide range of organic dyes and simulated hospital effluents

The present work reported the utilization of Fe3O4@C nanocomposite for removing a series of six organic dyes from aqueous solutions and dealing with simulated hospital effluents. Single-step fabrication of magnetic Fe3O4@C nanocomposite was facilely performed at 500 °C. This material was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Core–shell Fe3O4 NPs (∼40 nm in average size) were dispersed well and encapsulated by ultrathin carbon coatings with the thickness of 4–5 nm. Fe3O4@C nanocomposite owned surface functional groups important for dyes adsorption. The adsorption results showed that maximum adsorption capacity values of organic dyes on Fe3O4@C obeyed an order as follows: methyl orange (38.03 mg/g) < rhodamine B (87.32 mg/g) < methylene blue (95.61 mg/g) < methyl red (153.1 mg/g) < congo red (165.3 mg/g) < crystal violet (181.6 mg/g). Two simulated hospital effluents could also be treated from 63.6–84.5% using this nanocomposite. In addition, Fe3O4@C could be reused up to 5 cycles without considerable decrease in uptake capacity. [Display omitted] •Six emergent organic dyes were adsorbed by magnetic Fe3O4@C (38.03–181.6 mg/g).•Nonlinear kinetic and isotherm models were fitted well.•Simulated hospital effluents could be rapidly treated (63.6–84.5%) for 30 min.•Fe3O4@C nanocomposite could be reused for at least five times.