Adsorption and Ozonation Kinetic Model for Phenolic Wastewater Treatment

A three phase fluidized bed reactor was used to investigate the combined effect of adsorption and oxidation for phenolic wastewater treatment. Aqueous solutions containing 10 mg·L−1 of phenol and ozone were continuously fed co-currently as upward flow into the reactor at constant flow rate of 2 and 1 L·min−1, respectively. The phenolic treatment results in seven cases were compared: (a) O3 only, (b) fresh granular activated carbon (GAC), (c) 1st reused GAC, (d) 2nd reused GAC, (e) fresh GAC enhanced with O3, (f) 1st reused GAC enhanced with O3, and (g) 2nd reused GAC enhanced with O3. The phenolic wastewater was re-circulated through the reactor and its concentration was measured with respect to time. The experimental results revealed that the phenolic degradation using GAC enhanced with O3 provided the best result. The effect of adsorption by activated carbon was stronger than the effect of oxidation by ozone. Fresh GAC could adsorb phenol better than reused GAC. All cases of adsorption on GAC followed the Langmuir isotherm and displayed pseudo second order adsorption kinetics. Finally, a differential equation for the fluidized bed reactor model was used to describe the phenol concentration with respect to time for GAC enhanced with O3. The calculated results agree reasonably well with the experimental results.