Four different solvent extraction systems are compared for aluminum (Al) separation in the presence of alkali metals, alkaline-earth metals, and transition metals. The octoxyacetic acid (OOA acid) is utilized as an Al extraction reagent for the first time, exhibiting high selectivity for Al. The impacts of the concentration of extractants, the equilibrium pH of the aqueous phase, and the concentration of phase modifier were studied systemically. The results indicate that the Al extraction efficiency using OOA/TBP (tributyl phosphate) system could reach 98.9 ± 0.63 % via a single-step solvent extraction process while maintaining negligible extraction for the other metal ions at the pH value of ∼ 4.2. Meanwhile, the separation factors (β) of Al over magnesium, calcium, manganese, cobalt and nickel reach the maximum values (βAl/Mg = 285157, βAl/Ca = 18275, βAl/Mn = 19271, βAl/Co = 10814, βAl/Ni = 5969). Slope analysis and infrared spectroscopic characterization confirm that the extraction of Al by the OOA/TBP system follows the cation exchange mechanism. The OOA/TBP solvent extraction system is promising for the efficient separation of Al, with potential applications in a wide range of practical scenarios.