Chemical Characterization of Terpene-Based Hydrophobic Eutectic Solvents and Their Application for Pb(II)...

Area of Science:

• Green Chemistry
• Environmental Science
• Separation Science

Background:

• Conventional solvents used in liquid-liquid extraction (LLE) are often toxic and non-eco-friendly.
• Natural terpenes like menthol and thymol offer potential as less toxic, more sustainable solvent components.
• Hydrophobic solvents are effective for extracting nonpolar analytes from aqueous solutions.

Purpose of the Study:

• To characterize and evaluate novel hydrophobic solvents derived from natural terpenes and organic acids.
• To assess the efficacy of these terpene-based solvents for the liquid-liquid extraction (LLE) of lead(II) ions (Pb(II)) from aqueous solutions.
• To optimize extraction parameters and identify the most efficient solvent system.

Main Methods:

• Preparation of hydrophobic solvents using natural terpenes (menthol, thymol) as H-bond acceptors and organic acids (C8, C10, C14) as H-bond donors.
• Characterization of solvent properties, including hydrophobicity and viscosity.
• Optimization of liquid-liquid extraction (LLE) parameters for Pb(II) removal.
• Application of optimized solvents and assessment of extraction efficiency.

Main Results:

• Prepared terpene-based solvents exhibited high hydrophobicity and low viscosity, suitable for LLE.
• Satisfactory extraction efficiencies for Pb(II) were achieved with simple, fast procedures and low solvent consumption.
• The thymol-decanoic acid (Thy-DecA) 1:1 solvent demonstrated the highest Pb(II) extraction efficiency at 98%.
• Menthol-octanoic acid (Men-OctA) 1:1 and menthol-decanoic acid (Men-DecA) 1:1 achieved 97% and 94.3% efficiency, respectively.

Conclusions:

• Hydrophobic solvents based on natural terpenes are effective and environmentally friendly alternatives for Pb(II) removal via LLE.
• The thymol-decanoic acid solvent shows superior performance for lead extraction compared to menthol-based systems.
• These green solvents offer a promising approach for sustainable metal ion separation in various applications.