Desulfurization of a commercial jet fuel by vapor phase ion exchange (VPIE) Cu(I)-Y adsorbents were studied in a fixed-bed adsorber operated at ambient temperature and pressure. When used with an activated alumina guard bed, Cu(l)-Y(VPIE) provides by far the best adsorption capacities. In general, the adsorbents tested for total sulfur adsorption capacity at breakthrough follow the order Selexsorb CDX < Cu(I)-Y(VPIE) < Selexsorb CDX/Cu(I)-Y(VPIE). The best adsorbent, Selexsorb CDX/Cu(I)-Y(VPIE) (layered bed of 25 wt% activated alumina followed by Cu(l)-Y), is capable of producing 38 cm(3) of jet fuel per gram of adsorbent with a weighted average content of 0.071 ppmw-S. The sorbent is also capable of producing about 50 cm3 of jet fuel with a sulfur content of less than 1 ppmw-S. These low-sulfur fuels are suitable for fuel cell applications. Regeneration tests have shown the sorbent capacity can be fully recovered using calcination/reduction methods. Gas chromatography-flame photometric detection results show that the :pi-complexation sorbents selectively adsorb highly substituted benzothiophenes from jet fuel, which is not possible by using conventional hydrodesulfurization reactors. The high sulfur selectivity and high sulfur capacity of Cu(I)-Y(VPIE) were due to pi-complexation.