Generalized kinetic model for the photocatalytic degradation processes: Validation for dye wastewater treatment in a visible-LED tubular reactor

Abstract

A novel generalized kinetic model was developed to predict the photocatalytic degradation of methylene blue and synthetic blue wastewater. The kinetic model was validated using nitrogen-crosslinking, ZnO-incorporated, and chlorophyll-sensitized phenolic resins as photocatalysts. The model considers the generation of reactive oxygen species (ROS), rate of electron-hole pair generation (Rg), and the attack of ROS on the pollutant. The six-flux model was used to elucidate the absorption and scattering of photons in a visible-LED tubular reactor, while the extended effective quantum yield model helped to calculate the harnessed energy by the photocatalyst; both parameters were employed for the calculation of Rg. The model showed robustness and high accuracy (R2 >0.85) under several operational conditions for dye-containing water. When the physical-chemical characteristics of the semiconductor and the reactive media are added to the kinetic model, it represents a major step in the process engineering of heterogeneous photocatalysis systems.