Synthesis of magnetically separable porous carbon microspheres and their adsorption properties of phenol and nitrobenzene from aqueous solution

Magnetic porous carbon microspheres have been synthesized by a carbonization process of chitosan microspheres containing iron precursors. The structure and morphology of the magnetic porous carbon microspheres were characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), ⁵⁷Fe Mössbauer spectroscopy, and N₂ adsorption-desorption technique. Using phenol and nitrobenzene as model pollutants, the magnetic porous carbon microspheres showed good adsorption capacities of 35 and 97 mg/g, respectively, and they can be regenerated after release in ethanol. During the adsorption and desorption cycles, the porous carbon microspheres were easily separated by an external magnetic field. About 80 and 84% adsorption capacity for phenol and nitrobenzene can be retained after five consecutive operations. Therefore, these magnetic porous carbon microspheres could potentially be applied in separation processes.