Study On Xylene Waste Gas Using UV-Fenton Process

In this paper,xylene contained in the organic waste gas which from the self-made bubble column reactor was oxidized by UV-Fenton.Under different UV wavelengths,the effects of reaction conditions such as the dosage of H₂O₂ and Fe²⁺,initial pH,initial concentration,reaction temperature,residence time of gas on the degradation of xylene were studied.The degradation mechanism of xylene by UV-Fenton was also investigated.Experimental results showed that pH had great impact on xylene removal efficiency.When the pH value was above 3,the removal rate of xylene decreased sharply.The removal rate of xylene decreased after the gas residence time increased.The optimum residence time was 55s.When the pH was 3,the gas residence time of 55s,the initial concentration of xylene was 350mg/L,over 90%xylene was degraded.In this experiments,the dosage of H₂O₂ and Fe²⁺had little impact on xylene removal efficiency but on the utilization rate of H₂O₂.H₂O₂ was being put to better use,when the dosage of H₂O₂ and Fe²⁺were 0.1%and 40mg/L.When the dosage of Fe²⁺was 40mg/L,the way of several times with a small amount of adding H₂O₂ was favorable for the improvement of H₂O₂ utilization rate.In this papert,different effects of oxidation systems of UV,UV-H2O2,UV-Fenton on the performance of xylene oxidation were compared.The results showed that when the UV wavelength was 254nm and 185nm differently,UV cooperated with fenton.However,the uv wavelength of 185nm could get better result.In addition,through the study of uv-fenton oxidation system reaction mechanism,it was found that the oxidation mechanism of UV-Fenton,UV-H₂O₂ and Fenton was the same,the xylene oxidized by produced hydroxyl radicals.