Combination of column adsorption and supercritical fluid extraction for recovery of dissolved essential oil from distillation waste water of Yulania liliiflora

BACKGROUND Aromatic waste water is the main by-product of industrial essential oil distillation. To recover the dissolved essential oil from this distillation waste water, an approach combining column adsorption (CA) and supercritical fluid extraction (SFE) was proposed. Yulania liliiflora was selected as a case study. Activated carbon of mixed porosity was employed and quantitative desorption of the adsorbed oil was achieved using supercritical carbon dioxide (SC–CO 2 ). RESULTS The optimized condition of CA-SFE was 18 MPa, 308 K, dynamic extraction for 60 min and CO 2 flow rate of 3.6 g min −1 . A recovery of 0.668 ± 0.050 g kg −1 ( n = 3) was achieved for the dissolved oil from distillation waste water, significantly higher ( P < 0.05) than that obtained by liquid–liquid extraction (LLE) (0.405 ± 0.032 g kg −1 , n = 3). Yulania liliiflora recovered oil was rich in eucalyptol (52.6–55.2%), α -terpineol (15.2–18.1%) and terpinen-4-ol (8.1–8.7%). CONCLUSION The CA-SFE approach is highly efficient and especially suitable for large-scale application. The recovered essential oil is valued for being rich in organoleptically important and biologically active compounds. © 2015 Society of Chemical Industry