Regenerable CuO/γ-Al2O3-Reduced Graphene Oxide Adsorbent with a High Adsorption Capacity for Dibenzothiophene from Model Diesel Oil

This research focused on the removal of dibenzothiophene (DBT) from model diesel oil using CuO-loaded γ-Al2O3–reduced graphene oxide (CuO/γ-Al2O3–RGO) as an adsorbent, which possesses the highest adsorption capacity among reported regenerable graphene-related materials. The boehmite–RGO supports were synthesized using a one-pot hydrothermal synthesis method. As the RGO sheet surfaces are completely covered and isolated by boehmite nanorods formed via hydroxyl condensation of [Al(OH)x](3–x)+ or Al(OH)3 and the −OH of graphene oxide (GO), the specific surface area of boehmite–RGO increased to 378 m2/g, which is 20.8% higher than that of RGO (313 m2/g). CuO/γ-Al2O3–RGO adsorbents with different CuO contents were prepared, and their DBT adsorption desulfurization properties were evaluated. With a 2% mass ratio of CuO to boehmite–RGO, CuO/γ-Al2O3–RGO displays the highest DBT adsorption capacity (6.0 mg S/g) under ambient conditions, which improved by 53.8% in comparison with that of pure RGO (3.9 mg S/g). Moreover, the regeneration of the CuO/γ-Al2O3–RGO adsorbent is much more practical than that of the pure RGO adsorbent.