Abstract
Polymeric precursor procedure was employed in the synthesis of nitrogen-doped carbon-encapsulated alpha-Fe2O3 (NCF) nanocomposite (NC) at 325 degrees C. Electron microscopic studies confirm the formation of encapsulated alpha-Fe2O3 nanoparticles (similar to 20 nm) in nitrogen-doped carbon matrix. X-ray diffraction, Fourier-transform infrared spectroscopy, energy dispersive, and X-ray photoelectron spectroscopy studies were used to confirm the presence of nitrogen containing carbon in NCF-NCs. The NCF-NC was used as an efficient adsorbent in the removal of Cd(II) ion from aqueous medium. Batch adsorption studies were performed to optimize the various adsorption parameters such as contact time (2-240 min), pH (2-8), temperature (25 degrees C-45 degrees C) and initial concentration of Cd2+ ion (20-100 mg/L). The optimum pH and time for the adsorption of Cd2+ were 6.0 and 120 min, respectively. The course of adsorption was described by Langmuir and Freundlich isotherms and better correlation coefficient was achieved for Langmuir model. The maximum adsorption capacity at 25 degrees C was 208.3 mg/g by using the Langmuir equation.