Persulfate-based advanced oxidation processes (AOPs) for organic-contaminated soil remediation: A review

Sulfate radical-based advanced oxidation processes (AOPs) have been applied in soil remediation to degrade traditional pollutants in situ, such as polychlorinated biphenyls (PCBs), diesel, polycyclic aromatic hydrocarbons (PAHs), and total petroleum hydrocarbons (TPH). Emerging pollutants such as pesticides, pharmaceuticals, and phthalates have gradually entered the treatment list, and removal technology has been optimized from simple persulfate addition to coupling with various activation methods, including iron activation, thermal activation, base activation, and electrical activation. Peroxydisulfate (PDS) is widely used as oxidant in soil remediation due to its low cost and long environmental retention time. Experimental parameters and some soil properties significantly impact the contaminant removal rate. Changes in soil geochemistry, biology, and contaminant dynamics occur after application of this technology. The degradation rate of contaminants in soil is generally characterized by a pseudo-first-order reaction kinetic model. Other mathematical models have also been developed to understand the oxidation process. This review provides an overview of persulfate-based AOPs for organic contaminated soil remediation, especially for the deep understanding of the activation mechanisms and influential factors.