(84bk) Removal of Insecticides from Wastewater Using Ionic Liquids: A Computational Study

Insecticides play a major role in contaminating water sources and making them unfit for use. They are considered toxic and hazardous, and can enter the food chain. To overcome this issue, ionic liquids with their distinguished thermophysical properties are considered green and efficient solvents. In this study, a number of 165 ILs of different combinations of 33 cations and 5 anions were screened using the simulation software the COSMO-RS (Conductor-like Screening Model for Real Solvents) to extract organochlorine insecticides from water by predicting the selectivity and the capacity of ILs at infinite dilution. Density functional theory (DFT) was implemented with COSMO-RS to study the chemical nature on insecticides. Benzene hexachloride (BHC), Heptachlor, Aldrin, Gamma-Chlordane (γ-Chlordane), Endrin, and Methoxychlor are the chosen organochlorine insecticides compounds to be studied. Results show that Endrin and Methoxychlor reflect their chemical nature to be strong H-bond acceptors and weak H-bond donors, while other compounds act as H-bond donors with no possibility of being H-bond acceptors. Besides, it is found that ILs consisting of halides and heteroatomic anions combined with cations provide better selectivity and capacity for insecticides. However, the increase in the alkyl chain length of some ILs based-imidazolium decreases the selectivity and capacity as shown in Figure 1. Moreover, the hydrophobic phosphonium-based ILs deliver better selectivity and capacity to insecticides. In addition, ILs are considered green and efficient solvents to extract insecticides from water.