Hydrophobic Eutectic Solvents for Sustainable Bisphenol A Extraction from Water: Screening and Selection Based on Key Performance Criteria

Hydrophobic Eutectic Solvents (HES) are emerging as a promising class of sustainable solvents for water treatment applications, yet their rational selection and performance evaluation remain limited. In this work, we adopted a systematic approach to rank a diverse set of HES, combining terpenes, fatty acids, and trioctylphosphine oxide (TOPO). The screening was based on seven key criteria-viscosity, density, water leaching, pH shift, water uptake, EcoScale score, and chemical stability-aimed at identifying systems with low cross-contamination, high processability, and favorable environmental profiles. Selected HES were then evaluated in liquid-liquid extraction (LLE) using bisphenol A (BPA) as a model compound, with performance assessed via UV-Vis and NMR spectroscopy. The optimized HES, TOPO:menthol, demonstrated an excellent extraction efficiency and very low leaching. Reusability was explored as well as regeneration through back-extraction. Sustainability assessments using the Analytical EcoScale and AGREEprep tools reinforced the viability of the proposed systems. Beyond pollutant removal, this work offers a framework for the molecular-level design and evaluation of HES, advancing their integration into green separation technologies.