Synthesis of magnetic mesoporous carbon and its application for adsorption of dibenzothiophene

We synthesized magnetic mesoporous carbon (Ni-CMK-3) as an adsorbent for removal of sulfur from model oil (dibenzothiophene, DBT, in n-hexane). X-ray diffraction and transmission electron microscopy analyses revealed the presence of face-centered cubic Ni nanoparticles with an average size of 17 ± 3 nm, and indicated that the carbon support retained its mesoporosity and morphology after immobilization of the metal nanoparticles. Nitrogen adsorption measurements indicated that the resultant Ni-CMK-3 possesses high surface area (705 m2 g− 1), large pore-volume (0.87 cm3 g− 1) and average pore-size of 4.5 nm. The resulting magnetic mesoporous carbon afforded a maximum adsorption capacity of 62.0 mg DBT g− 1 of Ni-CMK-3 at the optimized conditions (Ni loading, 20%; adsorbent dose, 5 g L− 1; contact time, 1 h; temperature, 40 °C). Magnetic measurement revealed the ferromagnetic property of Ni-CMK-3 at room temperature with saturation magnetization, remanent magnetization and coercive force of 13.8 emu g− 1, 38.0 Oe and 2.2 emu g− 1, respectively, which made it desirable for separation under an external magnetic field. Following adsorption of DBT, Ni-CMK-3 could be separated by a magnet and regenerated by extraction with toluene. The regenerated adsorbent afforded 97%, 94% and 80% of the initial adsorption capacity after the first three regeneration cycles, respectively.