Screening of catalytic activity of natural iron-bearing materials > > towards the Catalytic Wet Peroxide Oxidation of Orange II

N. INCHAURRONDO; A. MAESTRE; G. ZERJAV; A. PINTAR; C. P. RAMOS; P. HAURE

Journal of Environmental Chemical Engineering

Elsevier

Año: 2018 vol. 6 p. 2027 - 2040

2213-3437

Natural materials were evaluated in the Catalytic Wet Peroxide Oxidation of a commonly used azo-compound, Orange II. Volcanic ash, black sand, pumice and Montanit300® were selected for evaluation. The materials were thoroughly characterized by several techniques (XRD, SEM/EDX, BET surface area and pore size distribution, TPD, Mössbauer spectroscopy, etc.). Peroxidation experiments were performed varying reaction temperature (50-80ºC), catalyst load and pH (3-8). Complete decoloration was reached in most experiments; however, mineralization levels, peroxide consumption and stabilities differed between materials. The activity of Fe leached during the reaction was evaluated and materials may behave as Fe dispensers. A combination of heterogeneous and homogeneous mechanism cannot be discarded. Long-term stability experiments were performed. While Montanit300® showed a decreased performance (20 % activity reduction in 16 h) due to a higher leaching (20 % Fe loss), ash and pumice performances remained almost steady at pH 3 (Fe loss: 3 % ash and 1.3 % pumice).Mineralization levels obtained were outstanding (40-70 %) and comparable to the performance showed by more sophisticated catalysts. The use of these natural materials will optimize the Fenton process economics, since they are really cheap, abundant and require only minimal modification.