Nano and micro-TiO2 for the photodegradation of ethanol: experimental data and kinetic modelling

With TiO2-photocatalysis being an effective alternative to other more expensive Advanced Oxidation Processes (AOPs), the possibility of using micro-sized TiO2 materials rather than the well-known nanosized powders is an important goal in terms of both handling safety and cost saving. In this work the photodegradation of ethanol, used as a model VOC (Volatile Organic Compound) molecule, was investigated, comparing the efficiency of both commercial nano- and micro- sized TiO2 samples. In all cases the same degradation pathway was observed, namely, a consecutive first-order reaction with acetaldehyde as an intermediate product and CO2 and water as the final products. All photocatalysts were characterized by means of XRD, TEM, IR, BET and XPS analysis. A kinetic model was also developed considering the collected experimental data and a regression of both adsorption and kinetic constants was made using MATLAB software. The optimized parameters were used for simulating the experimental data using an ode15s algorithm.