New aluminum mesh from recyclable material for immobilization of TiO 2 in heterogeneous photocatalysis

This study presents a new aluminium mesh made out of soda can rings as a support for titanium dioxide (TiO2) in the degradation of the synthetic dyes Bordeaux Red (BR) and Tartrazine (TT). Three pre-treatments including calcination and acidification steps were investigated in order to select the most efficient immobilization procedure for photocatalysis application. Raw and titania-aluminum meshes were characterized by scanning electron microscopy, x-ray diffraction, diffuse reflectance, and Fourier transform infrared spectroscopy. The material presented itself as a suitable alternative in the immobilization of titania for wastewater treatment. Preliminary tests selected H2O2/TiO2(suspension) oxidation systems under natural sunlight and germicidal lamps (UVC) exhibiting 97.2% and 99.5% of degradation in 180 minutes, respectively. Immobilized TiO2 systems reached high degradation rates (>99%) after 180 minutes in both UVC and solar light-based processes. An experimental planning study was carried out for the processes in order to find the best operational conditions and pseudo-first-order model fit well the removal data (discolouration rates of in the order of 0.0274 and 0.0145 min(-1) for UVC and solar light systems, respectively). Parameters such as TOC, COD, and turbidity, revealed a great improvement in the environmental quality of the water after the treatment and acute toxicity bioassays demonstrated a significant decrease in toxicity for both systems after the treatments. The TiO2-meshes demonstrated high performance in the removal after five cycles of operation. Therefore, the new immobilization procedure demonstrated that the TiO2-aluminum mesh is a feasible option for wastewater treatment and photocatalysis.