Fast and reversible adsorption for dibenzothiophene in fuel oils with metallic nano-copper supported on mesoporous...

Dibenzothiophene (DBT) in fuel oils causes the release of toxic sulfur oxide gases, and it is necessary to remove DBT in fuels. Herein, metallic copper was loaded on SBA-15 mesoporous silica through simple reduction reactions for the preparation of DBT adsorbents. On an adsorbent with a copper loading of 0.3 wt%, adsorption equilibrium was achieved within 5 min, and a DBT removal rate of 90.4% was achieved. The adsorption isotherm agreed with a linear Freundlich model and adsorption capacity was 12.1 mg sulfur/g. Nano-sized copper particles were observed by TEM, indicating the size effect of copper particles in DBT adsorption. A broad band, corresponding to copper-sulfur coordination bonds, was observed at 300-600 cm^-1 in the Raman spectrum of DBT-doped adsorbent. Meanwhile, the band at 1233 cm^-1 corresponding to C = C (-S) bonds in DBT was shifted to 1229 cm^-1 in DBT adsorbed. XPS and Cu LMM XPS spectra proved that Cu(0) was oxidized by DBT sulfur during adsorption. Furthermore, Auger spectra verified that the adsorption of DBT on Cu(0) involved the formation of Cu(I) and Cu(II) species through coordination bonds. The adsorption capacity could be completely recovered via elution. This work sheds light on the removal of DBT in fuel oils with cost-effective efficient adsorbents.