Exploring the use of hydrophobic ionic liquids in the alcoholic extraction of boric acid from high-magnesium brine

99.9% extraction, 99.8% boric acid recovery via 3-stage cross-current system. • [C10mim][TfO] reduces ethyl acetate consumption for eco-friendly extraction • DFT reveals H-bonding between the IL anion and boric acid drives extraction. • Excellent phase reusability and stability prove robustness for scalable use. This study develops a green extraction system for boric acid from saline lake brines using isooctanol, ethyl acetate, and the hydrophobic ionic liquid [C10mim][TfO] as co-extractant. Conventional solvent extraction often relies heavily on volatile organic solvents such as ethyl acetate, posing environmental concerns. Under optimized conditions (including [C10mim][TfO]/isooctanol fractions, pH, phase ratios, and cross-current stages), three-stage extraction and two-stage stripping achieved efficiencies of 99.9% each, yielding 99.8% overall boric acid recovery and a capacity of 28.7 g/L (as H₃BO₃). DFT calculations confirmed hydrogen bonding between the [TfO] − anion and boric acid as the key mechanism. Crucially, [C10mim][TfO] partially replaced ethyl acetate, reducing solvent consumption and environmental impact, while recirculation experiments confirmed excellent organic phase reusability and stability, demonstrating significant potential for sustainable industrial application.