Study On Advanced Oxidation Process Of Petroleum Contaminated Soil By Supported Iron Zeolite Heterogeneous Fenton

The treatment of soil contaminated by petroleum is urgent in China,homogeneous Fenton oxidation has become a promising technology in the field.While the pH should be controlled at 2³ as homogeneous Fenton oxidation technology treating the soil contaminated by petroleum,the low pH may destroy soil structure and do harm to the survival of microorganisms in the soil.Besides,the excessively fast reaction rate of homogeneous Fenton oxidation technology restrain the efficient removal of petroleum,and the violent reaction also limit the wide application of the technology in the soil remediation engineering.Heterogeneous Fenton system has got more and more attention for the relatively high pH,mild reaction rate and other advantages.The heterogeneous Fenton catalyst was prepared by loading iron on artificial zeolite in the study,the structure of the catalysts was characterized and then heterogeneous Fenton system was constructed.The influence factors and the reaction mechanism of the system oxydative degrading petroleum in soil were systematic studied.At last the step oxidation test of petroleum in soil by the system was carried out.The conclusions are listed as follows.?1?The analysis results of SEM,FTIR,XRD and XRF of the prepared catalyst indicated that the iron was loaded on the surface of artificial zeolite closely in the form of monodisperse?-Fe₂O₃,and the crystallinity of the zeolite loaded decreased.?2?The optimum reaction conditions of the heterogeneous Fenton system treating petroleum in soil varies according to petroleum pollution level.For mild polluted soil,the optimum condition was 0.2g catalyst and 0.75mL hydrogen peroxide?30%?per 1g contaminated soil,initial pH 6,temperature 20?,the removal rate of petroleum was 70.09%;For moderate polluted soil,the optimum condition was 0.2g catalyst and 0.6mL hydrogen peroxide?30%?per 1g contaminated soil,initial pH 6,temperature 20?,the removal rate of petroleum was 65.25%;For serious polluted soil,the optimum condition was 0.2g catalyst and 0.6mL hydrogen peroxide?30%?per 1g contaminated soil,initial pH 6,temperature 20?,the removal rate of petroleum was52.31%;?3?The fitting results of dynamics analysis showed that the oxydative degrade reaction of petroleum in soil by the system fit pseudo-second-order equation.The straight-chain paraffin in remaining petroleum increased and carbonyl decreased after the oxidation process,resulting in the benefit to the follow-up microbiological treatment.?4?The removal rate of petroleum was the highest as adding the oxidizing agent and heterogeneous Fenton catalyst one time for mild polluted soil.While for moderate and serious polluted soil,the highest removal rate was got as the heterogeneous Fenton catalyst was added by twice?the time interval was 6h?and through step oxidation,the removal rates reached 71.80%and 61.96%,respectively.