Journal of Hazardous Materials 271 (2014) 120–130 Contents lists available at ScienceDirect Journal of Hazardous Materials journal homepage: www.elsevier.com/locate/jhazmat Ultra-deep adsorptive desulfurization of a model diesel fuel on regenerable Ni–Cu/-Al 2 O 3 at low temperatures in absence of hydrogen Ali Mansouri, Abbas Ali Khodadadi ∗ , Yadollah Mortazavi Oil & Gas Center of Excellence, School of Chemical Engineering, Colleges of Engineering, University of Tehran, P.O. Box 11155/4563, Tehran, Iran highlights • Ni–Cu/-Al 2 O 3 sorbents show high activity in adsorptive desulfurization of diesel fuel. • Reduction temperature decreases significantly by adding Cu to Ni/-Al 2 O 3 sorbent. • Desulfurization temperature is considerably improved by adding Cu to Ni/-Al 2 O 3 sorbent. • Selectivity of Ni–Cu sorbents to sulfur in the presence of aromatics is improved. • Decrease in loss of adsorption capacity after regeneration of spent Ni–Cu sorbents. article info Article history: Received 7 October 2013 Received in revised form 6 January 2014 Accepted 5 February 2014 Available online 13 February 2014 Keywords: Adsorptive desulfurization Diesel fuel Dibenzothiophene Nickel Copper abstract A model diesel fuel containing 250 ppmw sulfur (as dibenzothiophene) in n-hexadecane was desulfu- rized at low temperatures in absence of hydrogen, down to about zero ppmw S on a novel adsorbent of well dispersed 3–12 nm Ni x −Cu 10−x (x = Ni wt%) nanoparticles formed by impregnation on -Al 2 O 3 and reduced in H 2 at 275 or 450 ◦ C. The sorbents were characterized by XRD, TEM–EDX, FESEM–EDS, H 2 –TPR, TPO, BJH and BET surface area measurement techniques. Effects of various parameters compris- ing Cu content, reduction and desulfurization temperatures, inhibition by naphthalene, and regeneration of spent sorbents were investigated. As copper is added to nickel: (a) the sorbent reduction temperature shifts to dramatically lower values, (b) sulfur adsorption capacity of the sorbents at lower reduction and desulfurization temperatures is significantly improved, and when 14 wt% Ni5Cu5 sorbent is added to the fuel, the sulfur content reduces from 250 ppmw S to about zero in less than 1 min, (c) loss of adsorp- tion capacity after the regeneration of the spent sorbent reduced at 275 ◦ C is significantly diminished, and (d) the selectivity of the sorbents to dibenzothiophene in the presence of naphthalene is improved. A higher reduction temperature tends to agglomerate nickel nanoparticles and reduce the sulfur adsorption capacity. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Environmental protection regulations tend to further reduce allowed sulfur content in the transportation fuels across the world. The U.S. Environmental Protection Agency (EPA) restricted the total sulfur content of diesel to 15 and that of gasoline to 30 ppmw S. European standard organization also limited the total sulfur con- tent of diesel and gasoline to 10 ppmw S [1,2]. Sulfur compounds in the fuels also poison the catalytic converter in automobiles and contribute to acid rain by producing SO x compounds. Therefore, ∗ Corresponding author. Tel.: +98 21 6696 7792; fax: +98 21 6696 7787. E-mail address: khodadad@ut.ac.ir (A.A. Khodadadi). deep desulfurization of fuels has become an important process in the petroleum refineries [1]. Hydrodesulfurization (HDS) is the conventional method for desulfurization of the fuels in petroleum refinery carried out in the presence of sulfided Co(Ni)Mo/-Al 2 O 3 catalysts at elevated operating temperatures (300–400 ◦ C) and H 2 pressure (30–100 bar) [3,4]. HDS is efficient for removing sulfides, disulfides, mercap- tans and thiophenes, but is less effective for removing refractory sulfur compounds such as benzothiophene (BT), dibenzothio- phene (DBT) and their alkyl derivatives such as 4,6-DMDBT [5]. Desulfurization of refractory sulfur compounds with HDS requires severe operating condition [6,7]. To reduce total sul- fur content of diesel from 500 to less than 15 ppmw S using http://dx.doi.org/10.1016/j.jhazmat.2014.02.006 0304-3894/© 2014 Elsevier B.V. All rights reserved.