Author Identifier (ORCID)
Abstract
The escalating global demand for lithium necessitates the development of efficient, selective, and environmentally sustainable extraction technologies from brine resources. This study presents a novel solvent extraction system employing dibenzoylmethane (DBM) as a lithium-selective β-diketone chelating extractant and 1-octanol as a biodegradable diluent for lithium recovery from alkaline salt lake brines. The effects of critical process parameters, including aqueous phase pH, extractant concentration, and total dissolved solids (TDS), on lithium extraction efficiency and selectivity were systematically investigated. Under optimized conditions (pH 12, 0.3 M DBM in 1-octanol), the system achieved a single-stage lithium extraction efficiency of 80.8% with exceptional separation factors of 309 (Li/Na), 381 (Li/K), and 502 (Li/Rb), following the selectivity order Li+ > Na+ > K+ > Rb+ consistent with the inverse ionic radii trend. Notably, increasing ionic strength enhanced extraction performance through a salting-out effect, yielding 88.5% lithium extraction and a remarkable separation factor (Li/Na) of 1113 at 4 M sodium concentration. A two-stage extraction strategy further increased cumulative lithium recovery to 97.06% with sodium co-extraction below 3%. The integrated extraction–scrubbing–stripping protocol, employing deionized water scrubbing and 0.5 M HCl stripping, produced lithium products with 96.2% purity. Validation using synthetic Zabuye Lake brine demonstrated 84.88% lithium extraction with separation factors of 493 (Li/Na) and 988 (Li/K), achieving 98.85% sodium removal and 99.72% potassium removal in a single cycle. Density functional theory (DFT) calculations at the M06-2×/def2-TZVP level corroborated the experimental selectivity, revealing a more negative binding energy for the DBMsingle bondLi+ complex (−231.57 kJ·mol−1) compared to DBMsingle bondNa+ (−176.22 kJ·mol−1) and a negative exchange free energy (ΔGex = −44.48 kJ·mol−1 under biphasic octanol/water conditions), confirming the thermodynamic preference for lithium complexation.
Keywords
1-octanol, dibenzoylmethane, direct lithium extraction, salt lake brine, solvent extraction
Document Type
Journal Article
Date of Publication
10-15-2026
Article Number
139226
ISSN
13835866
Volume
409
Publication Title
Separation and Purification Technology
Publisher
Elsevier
School
Mineral Recovery Research Centre / School of Engineering
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Gonbadi, M., Abrishami, S., Gholipour, O., Vafadar, A., & Razmjou, A. (2026). Green lithium extraction from alkaline brines using a dibenzoylmethane octanol system. Separation and Purification Technology, 409, Article 139226. https://doi.org/10.1016/j.seppur.2026.139226