An Experimental Study of Supercritical Adsorption Equilibria of Salicylic Acid on Activated Carbon

The supercritical desorption of solutes from porous media is a technology with a range of applications such as the treatment of contaminated soil and the regeneration of spent activated carbon. Although data in this field are scarce, previous studies have shown that supercritical adsorption equilibria have a significant role in defining supercritical desorption behaviour. The existing supercritical adsorption database is described and trends in the data are discussed. Expèerimental data for the system CO2 - salicylic acid - activated carbon are presented. A new apparatus incorporating dual high pressure syringe pumps and a high pressure UV cell was constructed to measure these data. Adsorption isotherms were measured at pressures between 90 and 250 bae and 308.1 K and 328.1 K. The influence of CO2 density and temperature on the adsorption equilibria is also studied. The adsorption data have been correlated with existing isotherm models.