Statistical parameter optimization and modeling of photodegradation of methyl orange using a composite photocatalyst...

Doping a transition metal into photocatalysts enhances the photocatalytic activity drastically. In the first part of this study, Taguchi design of experiment is applied to evaluate and optimize the efficiency of the Fe₂O₃/TiO₂ photocatalyst synthetized by thermal method assisted by UV radiation. The contribution percentages of Fe:TiO₂ mass ratio, Fe₂O₃/TiO₂ dosage, and pH on the total organic carbon (TOC) removal are determined using analysis of variance (ANOVA). In the second part of this study, in order to model the photocatalytic degradation process, the optical properties of the photocatalyst, including the extinction, absorption, and scattering coefficients, are determined. Subsequently, the radiation transfer equation (RTE) is solved numerically based on the surface emission model using the discrete ordinate method. Furthermore, a rigorous model, including chemical reaction rates, radiation transfer, and mass transfer is proposed and validated by a set of experimental data. A satisfactory correlation between the predicted and experimental data with less than 5% error confirms the reliability of the model. The intrinsic kinetic parameters are also determined by comparing predicted values to those of the experimental results by applying non-linear regressions.