Carbon-Based Materials for Oxidative Desulfurization and Denitrogenation of Fuels: A Review

Abstract

Sulfur (S) and nitrogen (N) are elements naturally found in petroleum-based fuels. S- and N-based compounds in liquid fuels are associated with a series of health and environmental issues. Thus, legislation has become stricter worldwide regarding their content and related emissions. Traditional treatment systems (namely hydrodesulfurization and hydrodenitrogenation) fail to achieve the desired levels of S and N contents in fuels without compromising combustion parameters. Thus, oxidative treatments (oxidative desulfurization–ODS, and oxidative denitrogenation-ODN) are emerging as alternatives to producing ultra-low-sulfur and nitrogen fuels. This paper presents a thorough review of ODS and ODN processes applying carbon-based materials, either in hybrid forms or as catalysts on their own. Focus is brought to the role of the carbonaceous structure in oxidative treatments. Furthermore, a special section related to the use of amphiphilic carbon-based catalysts, which have some advantages related to a closer interaction with the oily and aqueous phases, is discussed.

Metal-Free Catalytic Oxidative Desulfurization of Fuels─A Review

“…The amphiphilic character of the carbon materials can be effectively tailored to adjust emulsion formation and stability for ODS facilitated under emulsified systems. Further details on the classification of the carbon-based ODS catalyst systems and related examples can be found in a recent review by Roman et al…”

“…The amphiphilic character of the carbon materials can be effectively tailored to adjust emulsion formation and stability for ODS facilitated under emulsified systems. Further details on the classification of the carbon-based ODS catalyst systems and related examples can be found in a recent review by Roman et al 150 The development of ODS catalysts based on nanostructured carbonaceous materials requires diligent efforts to fine tune their surface properties. This could enable simultaneous promotion of their catalytic performance and stability with time on stream.…”

Modeling the Liquid Fuel Desulfurization Efficiency of Activated Carbons before and after Chemical Treatment: The Competitive Role of Mono- and Diaromatics

“…There is not a concise theory for the shape of the function k(Q) since it depends on the detailed structure of the material, so empirical functions of the following form are typically considered ) i j o h (12) where k o the value of k for the fresh adsorbent and k h is an inhibition coefficient designating the diffusivity reduction with the increase of Q. The pair of exponents (i,j) typically takes the values (1,1), (1,2), and (2,1). The usual procedure is to start with the first pair, and in case of unsuccessful fitting, the other pairs are considered.…”

“…Petroleum-based fuels, such as gasoline and diesel, include apart from hydrocarbons various other compounds with heteroatoms, with sulfur-containing molecules being the most abundant. 1 The combustion of the S-containing compounds leads to emissions of sulfur oxides and especially sulfur dioxide (SO 2 ), which is associated with disastrous effects both on the environment and in human health. These oxides are accountable for air pollution and the formation of acid rain, in addition to posing a threat in human's health when inhaled.…”

Quantitative Evaluation of Non-basic Nitrogen-Containing Compounds in Petroleum-Derived Samples by Direct Injection ESI (−) Orbitrap MS

“…8,12,13 During automobile fuel combustion, non-basic NCCs in contact with atmospheric water lead to hazardous gas formation (NO x ), which are responsible for causing numerous environmental (e.g., ozone formation and acid rain) and human health issues (e.g., dermatological and respiratory problems). 2,12,14 Hence, the chemical characterization of non-basic NCCs in crude oils and petroleum-derived samples is crucial for the petroleum industry. Ultrahigh-resolution mass spectrometry (UHRMS) has emerged as an appropriate tool for characterizing complex mixtures.…”