Catalytic wet oxidation of phenol on active carbon: stability, phenol conversion and mineralization

Catalytic wet oxidation (CWO) of phenol as model pollutant has been studied by using three commercial active carbons (AC) as catalysts. Runs were carried out in a fixed bed reactor, at 160 °C of temperature and 16 bar of oxygen pressure. All the AC tested showed high catalytic activity in both phenol conversion and mineralization. Small amounts of intermediates were found in phenol oxidation being the main compounds detected hydroquinone, p-benzoquinone, p-hydroxybenzoic acid, catechol and short chain acids (SCA) C2-C4, mainly maleic, acetic and formic acids. Only small amounts of oxalic acid were found in the liquid phase. These SCA were the most refractory compounds to catalytic oxidation.