Study On Oxidation And Degradation Of Toluene In Gas By UV Advanced Oxidation Technology

With the deterioration of air quality in our country, the fog and haze is increasing, and the control of volatile organic pollutants (volatile organic compounds, VOCs) in the air has attracted people’s attention. VOCs control technology at present mainly include combustion method, adsorption method, absorption method,condensation method, biological membrane method, corona method, etc., but these technology complex, high cost, difficult to engineering application. Advanced oxidation process because of its oxidation thoroughly, high reaction speed, high treatment efficiency, no pollution and so on, stand out in the past twenty years.This topic research uv advanced oxidation technology in the application of volatile organic pollutants treatment. The feasibility of treatment of toluene by two kinds of advanced oxidation processes of UV/Fenton and UV/H2O2 was studied, and the influencing factors of toluene degradation by advanced oxidation technology were studied.And on line monitoring of the exhaust gas after degradation of the two kinds of advanced oxidation technologies.In this study, toluene was used as a representative of volatile organic pollutants (VOCs) to investigate the performance of photo-Fenton reaction on decomposition of toluene by a flowing column. The effect of initial pH, H2O2 concentration, Fe2+concentration, initial concentration of toluene on degradation of toluene by photo-Fenton reaction. Mass spectrometry and gas chromatograph were utilized to detect the products. The results showed that the introduction of the UV greatly enhanced the Fenton reaction byimproving the generation of hydroxyl radicals.The toluene removal was more than 98%as the initial concentration of toluene was 260mg/m3 under the experimental conditions:initial pH=3.0, H2O2 20mmol/L, Fe2+ 0.3mmol/L. Furthermore, there is no other intermediate except CO2 was detected in the reaction that photocatalytic degradation of toluene in waste gas by the photo-Fenton, which indicates degraded toluene all mineralized into CO2.The use of UV/H2O2 system oxidative degradation of toluene gas, identified by UV wavelengths, UV light intensity, initial pH value of the solution of hydrogen peroxide, H2O2 concentration and other conditions.Mass spectrometry and gas chromatograph were utilized to detect the products.Results showed that UV/H2O2 system has very good effect on the oxidation degradation of toluene, In the toluene concentration 450 mg/M’3, gas flow 225mL/min-1, light intensity is 60W wavelength 254nm UV irradiation, the concentration of H2O2 mmol/L-1, pH is 5.0 experimental conditions, toluene has better removal rate, the maximum can reach 90% or so.The results showed that the UV/H2O2 reaction catalyzed degradation of toluene was CO2, and no intermediate products such as benzene and benzene were found.There are two kinds of reaction paths for the degradation of toluene in UV/H2O2 system:the degradation of toluene by direct excitation of UV light through effective photon, and the indirect oxidation degradation of · OH.