Enhanced and sustainable extraction of acetic acid from wastewater using a novel ternary deep eutectic solvent

Acetic acid is an irreplaceable raw material for the synthesis of key chemicals. However, its production is accompanied by the generation of large volumes of acidic wastewater, posing a significant environmental challenge. The strong polarity of acetic acid and water complicates its separation. The present study examines the effectiveness of binary and ternary deep eutectic solvents (DESs) in extracting acetic acid. A novel ternary DES composed of tri-n-butyl phosphate (TBP), tri-n-octylphosphine oxide (TOPO), and 1-Octanol was successfully synthesized and characterized using spectroscopic techniques. The ternary DES exhibited significantly higher extraction efficiency (up to 73.18 %) than the binary DES (TBP-1-Octanol), underscoring the synergistic effect of the third component. Cyclic extraction experiments demonstrated excellent recyclability, with a single-cycle efficiency loss of less than 2 % after six cycles. Molecular dynamics simulations further elucidated the extraction mechanism. This DES minimizes energy input and solvent emissions, thereby offering a low-energy, low-waste, and environmentally compatible alternative to conventional organic solvents.