Embodiments provide a method including: supplying the hydrocarbon feedstock to an oxidation reactor, where the hydrocarbon feedstock is oxidized in the presence of a catalyst to selectively oxidize sulfur compounds present in the hydrocarbon feedstock; separating the hydrocarbons and the oxidized sulfur compounds by solvent extraction; collecting a residue stream that includes oxidized sulfur compounds; supplying the residue stream to a gasifier to produce a syngas stream and a hydrogen sulfide stream; supplying the extracted hydrocarbon stream to a stripper to produce a stripped oil stream, which is then supplied to an adsorption column, such that the adsorption column can produce a high purity hydrocarbon product stream, a second residue stream, and a spent adsorbent stream, the spent adsorbent stream containing another portion of the oxidized compounds; and supplying the spent adsorbent stream to the gasifier to produce additional syngas for the syngas stream, thereby disposing of the adsorbent.