An adsorbent composition comprising a nanostructured titanium oxide material of the formula TiO.sub.2-, where 0.ltoreq..times..ltoreq.1 with nanotubular and/or nanofibrilar morphology, high oxygen deficiency, having an orthorhombic JT crystalline phase described by at least one of the space groups 59 Pmmn, 63 Amma, 71Immm or 63 Bmmb, and comprising between 0 and 20 weight percent of a transition metal oxide is used for the selective adsorption of nitrogen compounds and/or sulfur compounds from light and intermediate petroleum fractions.