Improved Fe2O3/Al2O3 as Heterogeneous Fenton Catalysts for the Oxidation of Phenol Solutions in a Continuous Reactor

LUCILA DOUMIC; CARLA DI LUCA; FERNANDO IVORRA; PAOLA MASSA; ROSA FENOGLIO; FRANCISCO MEDINA CABELLO

Almería

Conferencia; 3rd European Conference on Environmental Applications of Advanced Oxidation Processes EAAOP3; 2013

Phenol solutions are frequently studied as model effluents due to their high toxicity and resistance to traditional detoxification techniques. Different advanced oxidation processes have been applied to effectively treat phenolic wastewaters, including the classic Fenton?s reagent. More recently, this reaction system has been modified in order to develop heterogeneous Fenton catalysts capable of overcoming the limitations of the homogeneous catalysis (separation, pH control, etc). In general terms, these materials are prepared by immobilizing transition metal cations (primarily iron, but not exclusively) over different supports, and they are further tested in Catalytic Wet Peroxide Oxidation (CWPO) reactions, using H2O2 as oxidizing agent at mild conditions. Among low-cost materials, the potential of alumina supported systems has been only limitedly explored. We have investigated alumina based catalysts with promising results. From previous studies, we concluded that by means of a high temperature thermal treatment, the catalytic stability could be significantly enhanced. In the present work we continued studying Fe2O3/Al2O3 systems for the CWPO of phenol solutions. The objective was to reach higher degradation rates, minimizing the impact of leaching processes. For this purpose, pelletized catalysts were prepared using higher iron loading (6wt% Fe2O3) and different acid pre-treatments. A relatively concentrated phenol initial charge (5 g/L) was selected, which imposes more demanding reaction conditions for the catalyst in order to test the resistance of the iron species to solubilization. The experiments were performed in a fixed bed reactor, with continuous operation.