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

Abstract

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.