Advanced methods for removal of organosulfur pollutants from liquid fuels

The presence of sulfur in the liquid transportation fuels (gasoline, diesel and jet fuels) causes to air pollution and acid rain after fuel combustion. One of the major problems of industrial hydrodesulfurization (HDS) in deep-desulfurization of fuels, is low reactivity of thiophenic compounds. Therefore, the development of several alternative processes to produce clean fuels has been a high significant research issue in recent years. Extraction, adsorption and selective oxidation of the key sulfur pollutants, especially thiophenic compounds, appear among the alternative low-cost methods. Among them, catalytic selective oxidative desulfurization (ODS) process is now nearing commercialization and several researches have been published. In this paper, the recent enhancements in developing new catalysts designed for selective ODS of liquid fuels with a high efficiency have been investigated. These enhancements involved the development of new material such as supported and unsupported ionic liquids and polyoxometalates (POM), as well as the structural design to improve the activity, selectivity, or stability of the catalysts in the process.