A Comparison Between Trioctylamine (TOA) and Tris(2-Ethylhexyl) Amine (TEHA) in Solvent Extraction of Sulfuric Acid*

The study investigated the behavior of two amines, Trioctylamine (TOA) and Tris(2-Ethylhexyl) amine (TEHA), in the sulfuric acid extraction system, with varying concentrations of extractants and modifiers, as well as the temperature of the sulfuric acid extraction. The study found that TOA had a higher ability in the extraction of sulfuric acid and was less dependent on temperature. However, an increase in the initial sulfuric acid concentration resulted in a drop in acid extraction percentage when TOA was employed, while such a drop was not observed in the case of TEHA. The study also illustrated the necessity of using Octanol as a modifier, with different minimum levels required for TOA and TEHA. Additionally, Octanol showed a positive effect on the extraction level of sulfuric acid in the TEHA - H2SO4 extraction system, which can be considered an advantage in the facile stripping of the loaded organic phase. The slope analysis method revealed that more than 1 mol of TOA is necessary to extract 1 mol of sulfuric acid, while 1 mol of TEHA can absorb 2 mol of sulfuric acid. FTIR spectra analysis confirmed TOA's participation in the extraction of sulfuric acid and provided insights into the chemical bonds formed. Overall, the study provides a comprehensive understanding of the solvent extraction of sulfuric acid and can be useful in optimizing the extraction process for industrial applications.