Photocatalytic degradation of tetracycline in a stirred tank: computational fluid dynamic modeling and data validation

In this study, we performed a computational fluid dynamics (CFD) modeling of tetracycline photocatalytic degradation using rGO/ZnO/Cu as the photocatalyst. The photoreactor was an unbaffled dished bottom tank with a backswept impeller and four lamp tubes. The CFD equations were solved for light intensity, velocity, pressure, and concentration fields in time-dependent modes of the fluid regime. Our model was more complex than the previous studies in several ways: we modeled the system is 3D instead of 2D, allowed variation of light intensity and pressure throughout the photoreactor, and traced the change of key parameters over time during the initiation phase until the steady state was reached. The flow pattern was solved and visualized in the presence of mixer in vertical and horizontal cuts. Experimentally measured concentrations over time matched model predictions well but also indicated the need for yet more complex models incorporating more factors that affect reaction rates.