Enhanced distribution kinetics in liquid-liquid extraction byCO2-expanded solvents
Artikel i vetenskaplig tidskrift, 2020
Liquid-liquid extraction (LLE) is a useful extraction technique for highly complex samples, however, itsuffers from being slow due to mass transfer limitations. Carbon dioxide expanded liquids (CXL) is a goodreplacement of traditional organic solvents for extraction, and for the first time, the use of CXL in LLEwas evaluated. An equipment consisting of a high-pressure view cell with on-line gas chromatographyanalysis was built and validated, and thereafter used to obtain novel phase equilibria data of the CO2/n-octanol/water system. The system was connected on-line to HPLC to study the potential of CO2-expandedliquid-liquid extraction (CXLLE) of pharmaceutical contaminants in water. In comparison with tradi-tional LLE performed under similar experimental conditions, the addition of CO2as a viscosity-loweringentrainer significantly increased the speed of mass transfer. Changes in compound log D (octanol-waterdistribution ratio) values brought by the CO2expansion also proved the possibility of selectivity-tuningin CXLLE.