Synergist free solvent extraction of lithium from alkaline salt lake brines using thenoyltrifluoroacetone in octanol

The growing demand for lithium in energy storage applications necessitates the development of efficient and selective extraction technologies for recovering lithium from alkaline brines containing high concentrations of competing alkali metals. This study presents an investigation of a thenoyltrifluoroacetone (TTA)-octanol solvent extraction system for selective lithium recovery from high‑sodium brines, utilizing 1-octanol as an environmentally benign diluent without requiring any synergistic co-extractant. Through systematic optimization of key operational parameters including pH, extractant concentration, scrubbing conditions, and stripping agent concentration, the system demonstrated excellent performance with lithium extraction efficiency of 67.5% ± 3.4% and a maximum separation factor of 28.0 ± 1.4 at pH 12.0. The optimized scrubbing operation effectively removed 44.0 ± 2.2% of co-extracted sodium, while stripping with 1.0 M HCl achieved 81.3 ± 4.1% lithium recovery. Validation testing with synthetic brine mimicking the composition of Zabuye Lake, Tibet, demonstrated the system's industrial viability under extreme conditions, achieving 78.9 ± 3.9% lithium extraction, separation factors of 41.2 ± 1.5 (Li/Na) and 54.3 ± 1.7 (Li/K), and 53.4 ± 2.6% overall lithium recovery with exceptional sodium removal (98.27 ± 0.49%) and potassium removal (99.3 ± 0.35%) in a single-cycle operation. The use of biodegradable 1-octanol as the diluent provides significant environmental advantages over conventional petroleum-based solvents, aligning with sustainable chemistry principles while maintaining robust extraction performance. • Synergist-free TTA-octanol approach achieves Li/Na separation factor of 28.03. • Zabuye Lake brine validation: 78.96% Li extraction, 98.27% Na removal • Biodegradable 1-octanol replaces petroleum-based solvents as green diluent • Efficient operation at native alkaline brine pH minimizes pretreatment requirements