Mechanistic and adsorption equilibrium studies of dibenzothiophene-rich-diesel on MnO2-loaded-activated carbon: Surface characterization

Abstract

In this work, the preparation and characterization of MnO2-modified-activated carbon for selective removal of organosulfur compounds including dibenzothiophene were outlined. The deposited particles of the modifier were entrapped within the micropores and the resulting adsorbent was efficient to desulfurize in diesel with rich-sulfur (7055 mgS kg1). Removal of organosulfur compounds was positively correlated with the deposited MnO2 and the best efficiency was observed at surface loading 30.6%Mn. The comprehensive characterization tests indicated drastic changes in the physicochemical properties of the modified adsorbents. The main findings were: (a) particles of -MnO2 were accumulated within the microspores and (b) less acidic surface compared to activated carbon was created in all modifications. Scanning electron microscope pictures indicated the filling of the pores by particles of MnO2. The mechanisms of S-compounds removal by the modified adsorbent were elucidated with the aid of Infrared spectral analysis. Adsorption isotherms of dibenzothiophene were measured and the data were presented by different models. Dubinin-Radushkevich model confirmed that adsorption of dibenzothiophene was exothermic and both Jovanovi and Langmuir models indicated the homogeneity of the modified surface. Jovanovi? model gave the best prediction of the maximum adsorption capacity. Combustion qualities of deeply desulfurized diesel were found within the regulated limits.