In-situ soil remediation via heterogeneous iron-based catalysts activated persulfate process: A review

Accumulation of multiple organic pollutants in the soil is a huge threat to ecological systems and health of human beings. Iron-based catalysts, such as zero-valent iron (ZVI) catalysts, iron oxide catalysts, and supported iron-based catalysts are widely used in sulfate radicals (SO4•−)-based advanced oxidation process (SR-AOPs) for soil remediation as a result of their environmental friendliness, extensiveness, and low cost, etc. In recent years, SR-AOPs using iron-based catalysts have arousing attention for the degradation/mineralization of organic pollutants in polluted soil. It helps to accelerate the transformation of contaminants, as well as sustainable remediation and adaptability to complex soil environments. This paper concentrates on the progresses of the Fe-based catalysts in SR-AOPs for organically contaminated soil. General persulfate activation process and the radical free radicals generation are summarized in soil remediation. The changes of physicochemical properties (e.g., organic matter, naturally occurring minerals, pH, and microbial community) in soil after SR-AOPs treatment are particularly discussed. The applications of Fe-based catalysts for SR-AOPs in soil remediation are thoroughly investigated from the perspective of the internal interaction among pollutants, catalysts, and soil. Finally, the existing challenges for SR-AOPs by Fe-based catalysts used in soil remediation are proposed.