Deep eutectic solvents extraction of dibenzothiophene in model diesel

Organic sulfur compounds in diesel fuel produce SOx during combustion in vehicles, leading to severe environmental pollution and causing health issues. The U.S. Environmental Protection Agency has established increasingly rigid sulfur-content standards, which has led to intense interest in deep desulfurization of diesel fuel. However, current desulfurization technology is not sufficient to achieve the ultralow sulfur diesel (ULSD) required for use in highway vehicles. Deep eutectic solvents (DESs) appearing at the beginning of this century have become excellent extraction agents for the deep extractive desulfurization process, owing to its low cost, simple and environmentally friendly synthesis process, chemical stability, non-volatility, and being biodegradable. Research shows that DESs have better efficiency than traditional ionic liquids (ILs). Therefore, DESs are better suited for use in desulfurization. In this study, a new potassium salt-based DES was synthesized using potassium carbonate(K2CO3) and ethylene glycol (EG). This type of DES and 30 wt.% H2O2 were employed as extractant and oxidant separately for the desulfurization system. Various experiments were carried out on the process of oxidative desulfurization (ODS), extractive desulfurization(EDS) and extractive and oxidative desulfurization (EODS) to find the optimal desulfurization process with this new type of DES. The study found EDS to be the optimal desulfurization process, with a sulfur removal efficiency of 86% at 30[degrees]C after 2 hours, which is higher than most DESs.