Desulfurization activity of nickel supported on acid-treated activated carbons

Activated carbons from coal were treated with different acids and used as carriers. Ni catalysts supported on untreated and treated activated carbons were prepared by the excessive impregnation method and characterized using Brunauer-Emmett-Teller surface area characterization, X-ray diffraction, and X-ray photoelectron spectroscopy. The desulfurization activity of granular catalysts was evaluated at a fixed bed under a simulated gaseous mixture. The results showed the following: (1) the order of desulfurization activity is AC < Ni/AC < Ni/AC-H2SO4 < Ni/AC-HNO3: (2) the specific surface area of the original activated carbons (723 m(2)/g) is less than that of the activated carbons treated with nitric (831 m(2)/g) and sulfuric acid (803 m(2)/g): (3) acid treatment can affect the surface functional groups of activated carbons, and activated carbons treated with nitric acid can significantly increase C=O or C-O- functional groups, which can enhance the desulfurization performance of the catalysts; and (4) Ni and NiO species coexist in the activated carbons before desulfurization, but after desulfurization, Ni and NiO species disappear and Ni2O3 is observed, indicating that Ni species could be involved in the desulfurization reaction. (C) 2012 Elsevier B.V. All rights reserved.