A comprehensive mathematical model for analyzing synergistic effect of oxidation and mass transfer enhancement during UV-Fenton removal of VOCs

Abstract

Volatile organic compounds (VOCs) emissions are regarded as a worth concerned threat to human health. The UV-Fenton coupled with mass transfer enhanced process shows promising effects on VOCs treatment. However, the detailed mechanism and mathematical model for this method have not been established. This work focuses on the hypothesis and validation of a mathematical model for UV-Fenton removal of VOCs using activated carbon particles to enhance mass transfer efficiency. Based on the mathematical model of reaction-diffusion-mass transfer, a mathematical model is established by using a series of important parameters such as ub, Dg, Dl, Kial, Kla and hydroxyl radical lifetime. The proposed model in this study introduces the key parameter of synergistic factor, which greatly improves the consistency between the model predicted results and the experimental data (the determination coefficient R2 distribution range changed from 0.71–0.98 to 0.95–0.98). Moreover, it can also explain reasonably the steady trend of outlet VOC concentration after 30 min of reaction. The mathematical model confirms that the addition of activated carbon during the UV-Fenton reaction ensures mass transfer efficiency and considerably improves (growth from 2% to 54%) the VOCs removal efficiency due to the synergy between UV-Fenton oxidation and mass transfer enhancement. Meanwhile, it provides insight into fruitful utilization of the oxidation capacity in the oxidation reaction,and achieves the purpose of predicting the efficiency of VOC removal in the Fenton process.