Construction of deep eutectic solvents for high efficiency extraction of polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) are serious organic pollutions and important industrial raw materials which are abundant in fluid catalytic cracking (FCC) diesel. Therefore, it is necessary to find suitable approach to remove PAHs from FCC diesel under mild condition. In this study, a series of deep eutectic solvents (DESs) were designed and synthesized as PAHs extractants. The tetraoctyl ammonium bromide (TOAB) and ethylene glycol (EG) with the molar ratio of 1:2, TOAB:2EG, exhibited great single extraction efficiency towards naphthalene (NAP, 55.6 %) and anthracene (ANT, 92.3 %). The orthogonal experiment proved the alkyl chain length of quaternary ammonium salt influenced PAHs extraction mostly. The high extraction efficiency was attributed to the hydrogen bonds, p-π and π-π interactions between PAHs and DESs. This work advances the DESs as PAHs extractants with high extraction efficiency and broadens the applications of DESs.