CFD Modeling of UV/H2O2 Process in Internal Airlift Circulating Photoreactor

Abstract

UV chemical degradation is a low-cost and sustainable wastewater treatment technology that protects the environment. In this study, computational fluid dynamics (CFD), mass transfer, and photochemical kinetic models combined with the continuous flow mode of UV/H2O2 were applied for the photochemical reaction of internal airlift circulation photocatalytic reactor to improve the efficiency of the reaction. Results show that with the increase in gas flow rate, the turbulence intensity and internal circulation effect of liquid in the reactor can be enhanced under the condition of constant baffle spacing. The CFD simulation prediction results of the chemical components in the liquid flow show that H2O2 has a high correlation with the OH radical formation, which depends on the intensity of UV. Thus, the degradation rate of methylene blue (MB) has a high correlation with UV intensity. The degradation efficiency of MB is improved with the increase in gas velocity by comparing the experimental data with the numerical simulation data. The experimental data are generally lower than the numerical prediction data, and although a certain difference range is observed, the overall prediction results are better.