Degradation of pyrene in contaminated water and soil by Fe2+-activated persulfate oxidation: Performance, kinetics, and background electrolytes (Cl-, HCO3- and humic acid) effects

SO4 center dot--based oxidation technologies have been considered as key solution in polycyclic aromatic hydrocarbons (PAHs) degradation. This study constructed Fe2+-activated persulfate oxidation to degrade pyrene in water and soil by using batch and column experiments. Pyrene degradation kinetic in polluted water and effects of soil background electrolytes (Cl-, HCO3- and humic acid) on pyrene degradation were both investigated. The variation of soil properties during pyrene degradation in soil was evaluated. Polluted water remediation results showed that approximately 93.2 % of pyrene was degraded by 65 mM of persulfate with Fe2+/persulfate molar ratio of 0.25. In soil, 88.5 % of pyrene was degraded under the same persulfate concentration and Fe2+/persulfate molar ratio, and there was a slight decrease of soil pH (from 6.7 to 5.4). Cl-, HCO3- and humic acid in soil brought an adverse effect to pyrene degradation through scavenging SO4 center dot-. Column study of soil remediation proved the superiority of Fe2+ in activating persulfate, whose application in soil remediation can finally reduce soil pollution and simultaneously avoid the excessive soil acidification in in-situ remediation. In addition, by evaluating the soil organic matter and total organic carbon during the remediation process, it was found that the soil properties have been improved. Therefore, Fe2+-activated persulfate oxidation would be a feasible way to remediate pyrene polluted water/soil. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

The Fe2+-activated persulfate oxidation technology shows great potential in degrading pyrene in contaminated water and soil. Some background electrolytes in soil may hinder the degradation of pyrene, while the remediation process can improve soil properties.