Volumetric Investigation of Cu(II) And Hg(II) Aqueous Mixtures with {Tetrabutylammonium Bromide + Glycerol (1:3)} Deep Eutectic Solvents and Extraction Performances of {Tetrabutylammonium Bromide + Capric Acid/Oleic Acid} over Divalent (Cu and Hg) Heavy Metals

Abstract

In this study, density was measured for hydrophilic deep eutectic solvents based on tetrabutylammonium bromide (as hydrogen bond acceptor) and glycerol (as hydrogen bond donor) in a 1:3 mol ratio with an aqueous heavy metal (Cu/Hg) solution at various concentrations in the temperature range of 298.15− 348.15 K at atmospheric pressure. The excess molar volume, partial molar volume, excess partial molar volume, apparent molar volume, excess partial molar volume at infinite dilution, and isobaric expansivity were calculated to study the nonideal behavior of these pseudobinary systems. The obtained excess molar volumes (V m E ) of 72 systems were then fitted to Redlich−Kister-type polynomial expressions. In addition, the performance of the predictive conductor-like screening model for real solvents (COSMO-RS) model is capable of quantitatively observing the sigma surface, sigma profile, and sigma potential of the individual chemical species and six prepared deep eutectic solvents. The existence of bands was analyzed for hydrogen bond acceptors (HBAs), hydrogen bond donors (HBDs), and used metal salts using Fourier transform infrared (FTIR) spectroscopy. Hydrophobic deep eutectic solvents (DESs) removed heavy metal (HM) ions from the synthetic contaminated water stream. At lower concentrations of Hg 2+ ions, extraction efficiency showed a higher value of 98.85% with capric acid-based DESs. Similarly, the extraction efficiency for Cu 2+ ions reached a maximum of 54.25% in this study. Before and after extraction, the concentrations of divalent copper and mercury were analyzed using inductively coupled plasma optical emission spectroscopy (ICP-OES).