Oxidative Removal Of Pahs In Contaminated Soil By Modified Persulfate Systems

PAHs is a common organic pollutants in contaminated soil sites.persulfate is a new oxidation repair agent in organic pollutants contaminated soil sites,the choice of activator is the key of persulfate oxidation technology.In this study,PAHs contaminated soil were taken as study objects,persulfate activate effect by different carriers of hydrogen peroxide and mixed transition metal ion were evaluated respectively to screen the excellent persulfate oxidation systems,then the persulfate systems were added with surfactants for further modification and launched amplification reaction,a soil tank model was developed for in-situ remediation of PAHs contaminated soil using persulfate finally.The main result were as follows:Sodium percarbonate was the best activator in different carriers of hydrogen peroxide,the best removal rate of PAHs was 95.7%in the case of sodium persulfate activated by sodium percarbonate with the best dosage,the removal rate of PAHs was up to 97.4%after adding with surfactants;The optimal transition metal ion combinations for the activation of persulfate were 0.3 mmol·g-1 Fe2+ and 0.3 mmol·g-1 Mn2+,the persulfate activated by them keep a 99.8%PAHs removal rate;Although the removal effect of PAHs by activated persulfate system were decreased slightly in amplification reaction,the removal rate were above 93%;In the in-situ remediation simulation experiment,the removal rate of PAHs in soil by activated persulfate was over 95%after 120h reaction time,and the influence on organic matter in soil was poor,which indicated that the activated persulfate had huge engineering application potential.