Mechanical grinding of FeNC nanomaterial with Fe3O4 to construct magnetic adsorbents for desulfurization

Mechanically ground magnetically FeNC/Fe3O4 demonstrated excellent desulfurization efficiency of dibenzothiophene (DBT), easy separation process, and good regeneration performance with an external field, which was certified by theoretical calculation and thermodynamics analysis. [Display omitted] •The FeNC displays a sheet like porous structure which enables efficient adsorption of aromatic sulfur derivatives. Thermodynamics investigation demonstrates a negative value of ΔG, ΔH, ΔS, suggesting that the adsorption is exothermic reaction with spontaneous process.•The FeNC was mechanically ground with Fe3O4 to construct FeNC-700/Fe3O4 adsorbent for DBT adsorption which can be recycled for five successive runs with magnet in a quite easy, economical and eco-friendly manner. Herein, a series of 3D nitrogen doped porous carbon nanomaterials (FeNC) at different pyrolysis temperature were prepared, followed by a mechanical grinding method to construct magnetically nanocomposite (FeNC/Fe3O4) which was demonstrated for the desulfurization of dibenzothiophene (DBT) in model oils. The FeNC derived from the pyrolysis of iron salt and nitrogen-doped carbon precursors possess abundant porous structure, which is highly active in the physical adsorption of aromatic sulfur derivatives. Impressively, the as-prepared FeNC-700 are evidenced to yield an excellent desulfurization efficiency (95.1% for 200 ppmw), a remarkable estimated adsorption capacity (25.08 mg S/g for 200 ppmw), and a high selectivity for DBT. Theoretical calculation revealed that the adsorption behaviors towards DBT followed the pseudo-second-order kinetic model, displays a better fitting coefficient based on Langmuir isotherm equation. The thermodynamics results indicate that adsorption process over FeNC-700 was spontaneous and exothermic reaction since ΔG, ΔH, ΔS, all shows negative signs. Subsequently, the FeNC-700 was mechanically mixed with 20 nm Fe3O4 to produce magnetically nanocomposite (FeNC-700/Fe3O4) for the adsorption of DBT in a simple separation process by external field and can be regenerated five runs without significant weight loss. Therefore, this strategy greatly simplifies the experimental procedure and favors the regeneration of the adsorbents.