Activation of Persulfate Oxidation by Pyrolytic Derivatives from Petroleum Contaminated Soil: Efficiency, Mechanism and Resources Utilization

The petroleum-contaminated soil (PCS) was treated by oxygen-limited pyrolysis and converted into carbonized soil (CS) as persulfate activator, aiming to develop a high-efficient remediation and value-added reuse strategy for PCS. The effects of pyrolysis temperature and retention time on the remediation efficiency of PCS and the degradation efficiency of aniline (AN) by CS-activated persulfate oxidation system were investigated. When the pyrolysis temperature is 500 degrees C and the retention time is 60 min, the total petroleum hydrocarbon removal rate of PCS reaches 99.46%, there is little residual soluble organic matter and the ecological risk is very low. Scanning electron microscopy, Elemental analysis, Raman spectroscopy, Fourier-transform infrared, X-ray photoelectron spectroscopy show that the residual organic carbon in CS mainly exists in the form of graphitized carbon, with good stability and no acute toxicity. The degradation efficiency of AN and TOC are up to 96.09% and 68.13% within 6 hours, respectively. Quenching experiments show that non-radicals played a major role in activation of PS for AN degradation. The main active substances are holes and singlet oxygen. The electropositive holes can adsorb S2O82-, capture the electrons in the organic pollutants and transfer them to the adsorbed S2O82-, thus accelerating the electron transfer and forming singlet oxygen, and improving the oxidation efficiency. This research provides an innovative resource utilization strategy for pyrolytic derivative from PCS, which can simultaneously achieve efficient remediation and value-added reuse of PCS.

Automated summary

The petroleum-contaminated soil (PCS) was treated by oxygen-limited pyrolysis and converted into carbonized soil (CS) as persulfate activator for efficient remediation and value-added reuse strategy. The effects of pyrolysis temperature and retention time on the remediation efficiency of PCS and the degradation efficiency of aniline (AN) by CS-activated persulfate oxidation system were investigated. The results showed that when the pyrolysis temperature is 500 degrees C and the retention time is 60 min, the total petroleum hydrocarbon removal rate of PCS reaches 99.46%.