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.

Conventional and Upcoming Sulfur‐Cleaning Technologies for Petroleum Fuel: A Review

“…Both USA and Canada have set the maximum level of sulfur in transportation diesel and gasoline to 15 and 30 mg S kg −1 , respectively, since mid 2006 . A much higher level (350 mg S kg −1 ) is permitted in transportation fuel in Jordan and some other countries . To respond to new and upcoming regulations, oil refineries face many challenges to comply with statutory limits regarding sulfur levels in liquid fuels.…”

“…In some cases, the organic/fuel layer is separated after completion of the reaction, and then the final sulfur level is measured. Owing to many analytical problems associated with the detection of OSCs in diesel, the most adopted method for quantification is an X‐ray fluorescence sulfur analyzer . This method offers a very low detection limit and a wide dynamic range in many petroleum products .…”

“…Owing to many analytical problems associated with the detection of OSCs in diesel, the most adopted method for quantification is an X‐ray fluorescence sulfur analyzer . This method offers a very low detection limit and a wide dynamic range in many petroleum products . Detection and quantification of DBT and other derivatives is also performed by using gas chromatography with flame ionization detection .…”

“…In fact, dibenzothiophene (DBT) and other common derivatives often constitute more than 50 % of the sulfur content in diesel . In a recent study, the authors of this review reported that 40 % of the OSCs in commercial diesel (7055 mg S kg −1 ) are present as dibenzothiophene . Many of the published research indicates that removal of aromatic sulfur compounds is rather limited if using the common hydrodesulfurization (HDS) method, which necessitates the pursuit of alternative methods.…”

“…Indeed, the process is rapid and is often recommended to reduce high levels of sulfur, but unfortunately, it suffers from a high running cost. A further disadvantage of HDS is the poor performance towards derivatives of DBT, even under the best operating conditions . The failure of HDS to remove intransigent derivatives of DBT, particularly 4,6‐dimethyldibenzothiophene (4,6‐DMDBT), has initiated new routes for removal including oxidation–extraction and adsorptive desulfurization (AD) to achieve ultraclean (<10 ppm w S) diesel.…”