Separation Science and Technology, Vol.38, No.5, 999-1014, 2003
Supercritical extraction of phenol from activated carbon fiber
Phenol was extracted from activated carbon fiber (ACF) using supercritical carbon dioxide in a fixed-bed extractor. Phenol was adsorbed to ACF from aqueous solutions at two different loadings, 277 and 402 mg phenol/g ACF. Supercritical extraction of the loaded ACF was carried out at temperatures of 30, 50, 70, and 90degreesC in a pressure, range from 206.8 to 344.7 bar. The extraction percentage of phenol from ACF was recorded as function of carbon dioxide used, and the trend of experimental data was extended by using an extrapolation technique. We observed a crossover point at which the extended isotherms of different temperatures could possibly intersect. This result reflects the combined effect of pressure and temperature on carbon dioxide density and on the desorption rate of phenol from ACF. The desorption rate constant was estimated from extraction profiles, which decreased with increasing temperature and pressure.