Degradation study of tris(2-butoxyethyl) phosphate with TiO2 immobilized on aluminum meshes employing artificial neural networks.

This work presents the study of tris(2-butoxyethyl) phosphate advanced oxidation in TiO2-containing systems. Titania was immobilized on aluminum surfaces from recyclable materials and the results were compared with the suspension system. The initial concentration of photocatalyst and the oxidizing agent was optimized in a 23 experimental design and a kinetic study of the reactions was performed in the selected conditions. The experimental data were fitted to the pseudo-first-order model (rate constants estimated at 0.0129 ± 0.0009 and 0.0079 ± 0.0006 min-1 for the systems with TiO2 in suspension and immobilized, respectively). Artificial neural networks were also employed to model the experimental data and they presented correlation coefficients superior to 0.98 in all the training operations. After five cycles of degradation, the TiO2-aluminum meshes exhibited a very low decrease in photocatalytic activity (inferior to 2%). Acute phytotoxicity assays demonstrated that the byproducts of the oxidation of TBEP molecules are less toxic than the raw samples regarding lettuce seeds. For both TiO2 systems, COD decreased considerably as a consequence of the degradation. The immobilized TiO2 system achieved similar degradation rates when compared with the suspension system.

Kinetic study of dye removal using TiO2 supported on polyethylene terephthalate by advanced oxidation processes through neural networks.

This work investigated the efficiency of polyethylene terephthalate (PET) as support material for TiO2 films in the photocatalytic degradation of red Bordeaux and yellow tartrazine dyes. The optimum operating conditions were determined by a factorial design, which resulted after 180 min of treatment in degradations of 99.5% and 99.1% for the UVC/H2O2/TiO2Sup and solar/H2O2/TiO2Sup systems, respectively. For the kinetic study, the experimental data fitted to the pseudo-first-order model and the calculated kinetic constants (k) values were 0.03 min-1 for the UVC/H2O2/TiO2Sup system and 0.0213 min-1 for the system solar/H2O2/TiO2Sup. It was verified that TiO2 supported in the PET remained with high degradation efficiency even after five cycles of reuse, indicating a good stability of the photocatalyst in the support. A significant reduction of TOC content was also observed along the reaction time. The phytotoxicity bioassay with Lactuca sativa demonstrated that after treatment with UVC/H2O2/TiO2Sup and solar/H2O2/TiO2SUP, an increase in IC50 and consequently lower toxicity was observed.