Partitioning Behavior of Anti-Inflammatory Drugs Using Aqueous Two-Phase Systems Based on Green Betaine Ionic Liquids

Abstract

Anti-inflammatory medications such as salicylic acid and acetaminophen are the most prescribed drugs in the world that could be found in the wastewater. Separation of these drugs from aqueous media has an economic and environmental impact. Recently, there has been considerable interest in utilizing aqueous two-phase systems (ATPSs) containing biocompatible ionic liquids (ILs) for the extraction of various substances due to their low cost and easy formation, while finding green materials to form these systems is challenging. Therefore, in this work, the phase diagram of novel ATPSs composed of two green betaine-based ILs, betaine hexyl ester bromide [BH]Br and betaine octyl ester bromide [BO]Br, and phosphate salts (K₃PO₄ and K₂HPO₄) have been investigated at 298.15 K and atmospheric pressure (≈85 kPa). The experimental binodal data were correlated by using an empirical nonlinear three-parameter expression developed by Merchuk. Then, the Setschenow-type equation and NRTL model were employed to establish correlations for the tie-lines. Finally, in these ATPSs, the partition behavior of acetaminophen and salicylic acid was investigated by measuring the partition coefficient and extraction efficiency. The results showed that the selected drugs were successfully extracted into the IL-rich top phase of the studied ATPSs, with partition coefficients greater than one across different tie-lines.