Extraction of diclofenac sodium from water using N-benzylethanolamine based ionic liquids: Computational and experimental approach

Despite the existence of numerous conventional wastewater treatment techniques, an efficient method for removing micropollutants remains elusive. Micropollutants (MPs) are chemicals that occur in trace amounts in the aquatic environment, which include pharmaceuticals, food additives, cosmetics, and dyes. The need to develop sustainable and cost-effective alternatives to eliminate these toxins has become a pressing issue. Recently, ionic liquids (ILs) have emerged as a potential candidate for wastewater treatment because of the ease in structure tunability and other unique chemical properties. This study aims to develop four N-benzylethanolamine based ionic liquids to eliminate diclofenac sodium, one of the top priority pharmaceutical micropollutants, from the aquatic environment. The ILs chosen were optimised with B3LYP theory and 6-311++G(d, p) basis set in Gaussian 16. Using integral equation formalism polar continuum model (IEFPCM) solvation as an aid, the interactions between the ILs and diclofenac medium were investigated. For the experimental studies, the liquid-liquid extraction (LLE) method was used, and parameters affecting extraction efficiencies (EE) such as IL concentration, rotation time, rotation speed, temperature, and equilibration time were optimised. The reusability of the best-performed IL was explored. Hydrophobicity, hydrogen bonding and π-π interactions were found to have a significant impact on the extraction efficiency of ILs.