Experimental and mathematical modelling of reactive dyes decolorization using fenton oxidation process in a microfluidic system

Abstract

Comprehensive experimental and mathematical studies for reactive dyes decolorization using Fenton oxidation in a microfluidic system were investigated. Reactive Yellow 181 (P2RN/181)and Reactive Blue 19 (RB19), were used as model solutions. The effect of process variables were experimentally and mathematically studied using Design of Experiments(DoE) approach. Mathematical modelling and fluid dynamic studies, using Computational Fluid Dynamics (CFD) modelling on COMSOL software were also implemented to validate the experimental work. Successful decolorization was achieved for both studied dyes in an in-house fabricated T-shaped microfluidic chip with serpentine channels. The DoE approach showed its suitability and effectiveness to optimize the Fenton oxidation process with better performance over previously published work. The optimum operational conditions were found to be 0.8 mM, and 35 mM, for Fe(II) concentration, H2O2 concentration, respectively. The highest decolorization percentages in the microfluidic system were found to be 92.9 and 96.0% for RY and RB, respectively at 100 ppm inlet dye concentration, 1.6 mM inlet Fe(II) concentration, and 70 mM H2O2 inlet concentration, flowing at a rate of 20 µL/s. CFD results obtained from the microfluidic system revealed 92.8% and 92.3% decolorization efficiencies from RY and RB, respectively after 200 s. The model prediction only deviated by 1.08% (for RY) and 3.85% (for RB) from the experimental values, indicating a very good agreement between the CFD and the experimental results, thereby, successfully validating the proposed model.