Remediation Of Petroleum Hydrocarbon Contaminated Soil By CMC Solubilization And SPS Oxidation

Oil, as an important energy source, is constantly being exploited and utilized. Meanwhile, it brings more and more pollution to the soil environment. Soil oil pollution not only destroys the structure and function of soil, but also becomes a long-term pollution source of surface water and groundwater. It may also enter into the atmosphere and cause adverse effects on human health. Chemical remediation is a rapid and effective technique for soil remediation of oil contaminated soil. By adding chemicals to the contaminated soil, the pollutants are oxidized or separated from the soil. CMC solubilization-SPS oxidation technology can effectively remove oil pollutants in soil.In this paper, firstly, by using the surfactant CMC to solubilize petroleum contaminated soil, we studied the solubilization efficiency and its influencing factors; Then we used the activation of sodium persulfate treatment of petroleum contaminated soil to study the oxidation of petroleum hydrocarbons and its influencing factors; Finally, we usd the CMC solubilization and SPS chemical oxidation combined remediation to deal with the contaminated soil to research the efficiency and operation conditions of the combined remediation; the conclusions are as follows:(1)the solubilization of surfactant CMC is good for the petroleum hydrocarbons in soil, and the solubilization time of 24 h is more appropriate. The solubilization rate of high concentration contaminated soil was higher than that of low concentration contaminated soil; When the concentration of CMC solution was 0.5%, the efficiency of petroleum hydrocarbon solubilization was higher in the soil. The alkaline condition was favorable for the solubilization of TPHs from contaminated soils, while the acidic condition might inhibit the solubilization of TPHs. With the increase of salinity, the solubilization of TPHs was enhanced significantly. The test of used CMC solution reuse showed that the used CMC solution still has a certain TPHs solubilization effect. It can be reused, and the solubilization ability of the surfactant can be fully utilized.(2)The operation conditions of the SPS oxidative remediation of petroleum hydrocarbons contaminated soil were determined by orthogonal experiments. The SPS concentration was 0.5mol/L, the concentration of FeSO4 was 0.5mol/L, the concentration of CA was 0.0125 mol/L, and the reaction time was 48 h. Compared with the removal rate of petroleum hydrocarbons of the different water soil ratio, the removal rate of petroleum hydrocarbons in high concentration contaminated soil was higher than that in low concentration; And both of them in the water soil ratio of 1:1, the removal rate reached the highest.So both for the high concentration and low concentration contaminated soil, the best water soil ratio was 1:1. At the same time, adding SPS or FeSO4 in batches could not improve the removal rate, instead, it increased the difficulty of operation. Therefore, for SPS and FeSO4, we adopt the method of one-time join.(3) CMC solubilization and SPS chemical oxidation combined remediation had a good effect on artificial petroleum hydrocarbon contaminated soil, and it could greatly improve the removal rate of petroleum hydrocarbons, especially for low concentration contaminated soil. Fe2+/SPS chemical oxidation method was used to deal with the waste supernatant from the contaminated soil. The dosage of oxidant SPS was more suitable for 3g/L, and the Fe2+/SPS chemical oxidation method could be used as a pretreatment for the final treatment of the waste liquid. For the actual contaminated soil, the removal rate of the soil was 87.4% and 78.6%, respectively, by using the method of first solubilization and the first post oxidation; the treatment efficiency was higher than that of the single solubilization repair or chemical oxidative repair. After solubilization first oxidation treatment than after the first oxidation solubilization way was more efficient. Therefore, it was suitable for the practical engineering to use the method of first solubilization and then oxidation treatment. For the waste supernatant from the actual contaminated soil remediation, the dosage of oxidant SPS was more suitable for 3g/L. CMC solubilization-SPS chemical oxidation combined remediation of petroleum hydrocarbon contaminated soil process flow including solubilization, gravity clarification, soil chemical oxidation, supernatant recycling and chemical oxidation. The technology was a kind of green environmental protection technology.