Reaction network and kinetic modeling of wet oxidation of phenol catalyzed by activated carbon

A detailed kinetic model for the catalytic wet oxidation (CWO) of phenol with a commercial activated carbon as catalyst has been proposed. Experimental data have been obtained under kinetic control at steady state in a three-phase fixed bed reactor with concurrent up flow. The kinetic model is able to predict the appearance and disappearance of phenol and the cyclic organic intermediates formed along the phenol oxidation progress. As some cyclic oxidation intermediates-such as hydroquinone and pbenzoquinone-are two orders of magnitude more toxic than phenol, this detailed model is required to design a CWO process achieving the detoxification of the influent. Influences of oxygen pressure and temperature have been quantified (in the ranges 127- 160 C and 3.4-16 bar, respectively). This model also considers the formation of refractory compounds to the CWO (short-chain acids as, i.e., acetic, maleic and formic acids, which are biodegradable). Besides, a constant value of the overall fractional yield for the oxidation of phenol, as target pollutant to CO2, has been obtained. The discriminated kinetic model fits quite well the experimental data for the whole range of variables used.