High performances of mesoporous g-C3N4 for adsorptive desulfurization in model gasoline (iso-octane) solutions

Highlights: • Acidized mesoporous g-C₃N₄ have an ever-large desulfurization capacity and fine selectivity for thiophene. • The adsorptive desulfurization performances could be recovered by heat-treatment followed by an acidizing process. • The high performance of adsorbent was attributed to the D-A interactions between the g-C₃N₄ and S atoms at thiophene. The desulfurization performance and mechanisms of mesoporous g-C₃N₄ as adsorbent in iso-octane solutions are presented. Mesoporous g-C₃N₄ was synthesized at 600 °C with a hard-template method using three types of silica-gels as template agent. XRD diffraction patterns show the interlayer distances of g-C₃N₄ are enlarged due to the intercalation of H⁺. The as-prepared adsorbents possess a large sulfur capacities and excellent selective adsorption for thiophene in a benzene/iso-ocatane mixed solution. TPD and regeneration experimental tests demonstrate that the larger sulphur-capacities could attribute to H⁺-intercalation. The adsorptive mechanisms of the thiophene over mesoporous g-C₃N₄ are interpreted by a novel donor-acceptor (D-A) interaction, where the donor is the S-atom of thiophene and the acceptor is the C-atoms in g-C₃N₄. Gaussian computation indicates the ortho-C atoms of N-atoms bonded with H⁺ are the main active sites for D-A interactions.