Manganese-Loaded Activated Carbon for the Removal of Organosulfur Compounds from High-Sulfur Diesel Fuels.

The adsorptive capacity of activated carbon (AC) is significantly enhanced toward weakly interacting organosulfur compounds (OSC) from sulfur-rich diesel fuel. Sulfur compounds are selectively removed from diesel after surface modification by manganese dioxide (MnO₂). A selective surface for OSC removal was created by loading MnO₂ on the surface; π-complexation between the partially filled d-orbitals of Mn⁴⁺ and the S atom is the controlling mechanism for OSC removal. Principal component analysis (PCA) of adsorption data indicated the significance of the Mn-AC mass and the temperature as experimental parameters according to the following correlation: OSC adsorption (mg Sg⁻¹)=3.94 (mass)−0.06 (part. diam.)−3.28 (temp)+0.02 (conc.). The kinetics of OSC adsorption confirmed that OSC removal by Mn-AC is a fast process in which 66 % of the surface is filled in 30 min. Kinetic data were best fitted by pseudo-first- and second-order models compared to diffusion-based models. Surface and pore diffusion has only a minor role in the process. [ABSTRACT FROM AUTHOR]