Mathematical modelling of an annular photocatalytic reactor for methylene blue degradation under UV light irradiation using rGO-ZnO hybrid

The application of heterogeneous photocatalysis in industrial scale has been hindered by a lack of simple mathematical models that can be easily applied to reactor design and scale-up. This work intends to use a simple mathematical model for predicting methylene blue (MB) degradation in a slurry-annular photocatalytic reactor using zinc oxide (ZnO) hybridized with reduced graphene oxide (rGO)-ZnO composite. The mathematical model presented may be used as a tool to design, scale-up, and optimize annular photocatalytic reactors for water and wastewater treatment. A mathematical model for the photocatalytic degradation of MB with rGO-ZnO under UV light irradiation was developed. This model was achieved by combination of Langmuir–Hinshelwood kinetics and Lambert–Beer law. The accuracy of developed model was checked for predicting MB degradation in other operation conditions such as different photocatalyst dosage and initial MB concentration. On the basis of these results, the accuracy of the model was tested under different experimental conditions, resulting able to be predictive in different operating conditions.