The present disclosure provides a method for removing sulfur compounds from a fuel containing sulfur compounds. The method includes contacting the fuel with an adsorbent that comprises a carbonaceous material doped with nanoparticles of aluminum oxide to reduce the concentrations of the sulfur compounds. The carbonaceous material is at least one selected from the group consisting of activated carbon, carbon nanotubes, and graphene oxide, and the adsorbent has a weight ratio of C to Al in the range from 3:1 to 30:1, and a weight ratio of C to O in the range from 1:1 to 10:1.