Abstract
In the coming decades, the importance of creating clean energy and its associated applications cannot be underestimated. Minimizing and eliminating toxic emissions has been proven to be critical to the survival of our planet. Sulfur (S) compounds in fuel create toxic emissions that pose a serious threat to the environment. Therefore, research on the desulphurization process has intensified worldwide to produce fuels with low S content. Traditional hydrodesulfurization (HDS) technology has not been widely adopted due to several disadvantages such as high cost, increased energy consumption, increased hydrogen production and the use of high content catalysts noble metals. A promising alternative to HDS is the extractive desulfurization (EDS) process due to its mild operating conditions. In recent years, much research attention has been paid to the use of deep eutectic solvents (DES), formed from a eutectic mixture of Lewis/Brønsted acids and bases. The purpose of this review is to discuss the advantages of EDS using DES compared to other desulfurization methods, as well as to describe various desulfurization factors such as the nature of DES, mass ratio of DES to fuel, temperature, mutual solubility, time, initial S content. The potential problems and shortcomings of EDS using DES have been well studied. Due to the promising physicochemical properties of DES, this review recommends DES as a preferred candidate over many molecular organic solvents in the field of clean petroleum fuel production.