THE OXIDATION OF AROMATIC HYDROCARBONS VAPORING WASTE AIR STREAMS USING VUV ADVANCED OXIDATION PROCESS

Introduction: The vacuum UV (VUV) system is a novel chemical-less advanced oxidation processes (AOP) used to decompose different class of organic contaminants. The present study aimed at investigating the efficiency of VUV process to degrade toluene as a model of aromatic hydrocarbons from the gas stream in a bench-scale photo-reactor. Materials and methods: The effect of various parameters including radiation flux, relative humidity, toluene concentration, and ozone dosage were investigated on toluene degradation in the VUV process. Results: The results showed that increasing the relative humidity up to 45% could considerably accelerate the oxidation of toluene as compared with the dry air stream in the process. Complete destruction of toluene was reached at radiation fluxes of 0.366 and 0.732 mJ/cm2 for 5 and 15 ppm of toluene, respectively. Dosing ozone into the VUV photo-reactor at the dosages of 20, 40 and 60 μg/s led to improve the toluene degradation from 65.6% to 100%. The removal of toluene in the VUV process under the selected optimum conditions followed a pseudo-first order reaction model with the degradation rate values of 5.99 mg/L.min. Conclusions: It was found that VUV process might be a novel and emerging AOP, which can efficiently perform for decomposition of aromatic hydrocarbons in contaminated air stream.