Continuous heterogeneous Fenton type process intensified by subsequent hydrodynamic cavitation for dye pollution abatement

STEFANIA NAPOLEONE; GABRIEL SALIERNO; M. AGUSTINA MAISTERRENA; MIRYAN C. CASSANELLO; LUCILA INES DOUMIC; M. ALEJANDRA AYUDE

Milan

Simposio; 11th International Symposium on Catalysis in Multiphase Reactors & 10th International Symposium on Multifunctional Reactors,; 2021

Advanced Oxidation Processes (AOPs) have been extensively tested for abatement of highly toxic and biocide contaminants [1]. Among them, the heterogeneous Fenton type (HFT) process poses many advantages related to the catalyst separation and reuse and negligible generation of sludge. Most of the works aimed at developing suitable catalysts and optimizing conditions of HFT processes have been carried out in batch mode [2]. Although results from batch experiments yield valuable information related to catalyst activity, it is difficult to properly test the catalyst stability. The continuous heterogeneous Fenton type (CHFT) process performed in a fixed bed reactor allows the treatment of large volumes of wastewaters with straightforward separation and recovery of the catalyst. Naturally, the catalysts should be particularly stable for a dedicated process carried out in a fixed bed reactor. Prussian blue, a mixed valence iron compound (ferric hexacyanoferrate?Fe4[Fe(CN)6]3) is a good candidate particularly for its very low solubility in water. The suitability of Prussian blue nanoparticles (PBNP) supported on -alumina for the catalytic peroxidation of the model dye Orange G (OG) in batch operation has been shown in previous contributions [3, 4]. The aim of this work was to study the capability of a fixed bed reactor formed by PBNP/γ-Al2O3 spheres for the continuous discoloration and mineralization of an OG solution. The influence of the flow rate, oxidant concentration and temperature was explored. Moreover, since hydrodynamic cavitation (HC) has been proposed as an excellent method for intensifying AOPs, and particularly HFT processes [5], it was applied in this case for intensifying the process efficiency. Thus, under certain conditions in which the output might still contained significant amount of reactive organic species (ROS), the liquid was collected and subjected to HC for optimizing the efficiency of the method.