Abstract
Activated carbon beds can be successfully used for safe and affordable purification of waste waters contaminated by toxic organic compounds, like PCB and Dioxins, as shown in previous works, using Phenol as model compounds. Furthermore, Supercritical Water Oxidation (SCWO) can be used for safe and efficient final destruction of the above mentioned toxic compounds. Therefore, regeneration of spent carbon beds using Supercritical Water (SCW) is quite interesting. To this purpose, the starting point is the quantification of Solid-Fluid Equilibrium (SFE) for the system made by activated carbon, Phenol, and SCW. A number of SFE measurements were made at laboratory scale under supercritical water conditions using a proper experimental apparatus along with a proper procedure. These data were used in combination with previously measured Solid-Liquid Equilibrium (SLE) data for the same system, in order to develop a new model able to quantitatively describe the phase equilibrium of the system under consideration from ambient to SCW P and T conditions. A Freundlich based equation was chosen and it was parameterized for comparison with the experimental data. As expected, since SCW behaves as an apolar solvent, the results obtained show that SCW can be successfully used for regenerating spent activated carbon under P and T values around 35 MPa and 720 K, respectively.
