Application of impinging jet atomization in UV/H2O2 reactor operation: Design, evaluation, and optimization

Abstract

The concept of augmenting UV/H2O2 reactor with impinging jet atomization to achieve highly efficient mixing and thin fluid sheet formation capability was investigated. The collision of two jets forming a free-standing thin liquid sheet allowed the establishment of an effective UV/ H2O2 advanced oxidation setting. The response surface methodology (RSM) was applied to model and optimize the photochemical degradation process, which provides three level designs for RSM fitting. Three variables namely, Re (15000–31000), impingement angle (60–120 degree) and H2O2 dosage (1000−3000 mg L-1) were applied in BBD to model and optimize the effects of three key operational parameters. The optimum methyl orange (MO) removal percentage (after 90 min) and the apparent first order rate constant were 93.6% and 2.438 min-1, respectively. The influences of initial dye concentration, UV radiation power, and jet diameter were also investigated as the other main operating parameters. ANOVA analysis indicated that the Re number has the highest impact of the three considered parameters and additional experiments showed that the jet diameter does not have any significant effect on MO degradation. A pseudo-first-order kinetic model was applied for the prediction of contaminant degradation and rate coefficients. The good agreements between the model predictions and experimental results indicate that the proposed model could successfully describe the effectiveness of the augmented UV/H2O2 reactor due to the maximum degradation of the model contaminant.