Kinetics of wet peroxide oxidation of phenol with a gold/activated carbon catalyst

Gold nanoparticles supported on activated carbon (Au/AC) have been tested in catalytic wet peroxide oxidation using phenol as target pollutant. In the current work, the effect of several operating conditions, including initial pH (3.5–10.5), catalyst load (0–6 g/L), initial phenol concentration (0.1–5 g/L), hydrogen peroxide dose (4–100% of the theoretical stoichiometric amount) and reaction temperature (50–80 °C) has been investigated. The results show that the Au/AC catalyst would be useful at relatively high pollutant to catalyst ratios (at least 0.4 w/w) and it can work efficiently within a wide range of pH (3.5–7.5). The catalyst suffers rapid deactivation but its activity can be completely restored by an oxidative thermal treatment at low temperature (200 °C). A kinetic model is presented, capable of describing the experimental results. This model is based on a rate equation of order one for hydrogen peroxide consumption and two for phenol oxidation and includes the catalyst deactivation and its temperature dependenceThe authors wish to thank the Spanish MICINN for the financial support through the projects CTQ2008-03988/PPQ and CTQ2010-14807. The Comunidad Autónoma de Madrid is also gratefully acknowledged for the financial support through the project S2009/AMB-158