Potassium Peroxoborate: A Sustained-released Reactive Oxygen Carrier with Enhanced PAHs Contaminated Soil Remediation Performance

Seeking for a safe, efficient, inexpensive, and eco-friendly oxidizer is always a big challenge for in-situ chemical oxidation (ISCO) technology. This study adopted the potassium peroxoborate (PPB), a novel peroxide, for soil remediation for the first time. PPB based chemical oxidation system (PPB-CO) could efficiently degrade polycyclic aromatic hydrocarbons (PAHs) without other reagents added, reaching 72.1 %, 64.2 %, and 50.0 % removal rates for naphthalene, phenanthrene, and pyrene after 24 h reaction, respectively. The superior total PAHs removal efficiency (60.6 %) was 3.6-4.7 times higher than that of other commercial peroxides (2NaCO•3HO, CaO, and HO). Mechanism analysis revealed that varieties of reactive oxygen species (ROS) can be generated by PPB through Fenton-like or non-Fenton routines, including HO, perborates species, O, •OH, and O. The sustainable generation of HO reduced the disproportionation effect of HO by 86 %, significantly improving the utilization rate. Moreover, sandbox experiments and actual contaminated soil remediation experiments verified the feasibility of PPB-CO in a real polluted site. This work provides a novel strategy for effectively soil remediation, highlighting the selection and application of new oxidants.