Evaluation and optimization of a new design photocatalytic reactor using impinging jet stream on a TiO2 coated disc

Abstract

Impinging jet stream on a TiO2 coated disc is applied as a new photocatalytic reactor for wastewater treatment. The modified sol-gel method and Spin coating technique were used for the catalyst synthesis and coating process, respectively. The synthesis TiO2 film was characterized using scanning electron microscopy and X-ray diffraction. Box-Behnken design with three variables like flow rate (2000–4000mLmin−1), coating disc diameter (18–22cm) and nozzle-to-disc distance (5–25cm) was applied to model and optimize the effects of three key operational parameters. The optimum removal percent of phenol (after 180min) and the apparent first order rate constant were 99.2% and 0.01313min−1, respectively. The influences of light irradiance, pH, phenol initial concentration, and disc rotation were investigated as other main operating parameters. The results showed that complete removal of a 30mgL−1 solution of phenol was obtained within almost 150min of applying disc rotation more than 100rpm. Finally, the residence time distribution (RTD) analysis is used as a tool to study the flow behavior of the new reactor and the results indicate that the reactor behavior properly fitted a tanks-in-series model with five tanks.