Halogenated Organic Pollutant Degradation Driven by Fe(II) Redox Chemistry

Fe(II) species play an important role in the global biogeochemical cycles of many other elements and the degradation of organic and inorganic compounds. However, the degradation effect of Fe(II) alone on pollutants, especially on highly toxic and persistent halogenated organic pollutants (HOPs), is extremely limited. Moreover, for a long time in the past, research efforts were mainly focused on the reductive reactivity of Fe(II) under anoxic conditions. In recent years, significant breakthroughs have been achieved in the electron transfer mechanism, reactivity regulation, and application scenarios of Fe(II). The aim of this review is to summarize these latest advances and the application progress of Fe(II) in HOPs degradation. Emphasis is placed on summarizing the structure–activity relationship of Fe(II), the regulatory strategies for Fe(II) reactivity, the interaction mechanisms between Fe(II) with H2O and dissolved oxygen at the solid–liquid interface (especially the formation processes of H• and •OH), and the reduction–oxidation synergistic technologies for HOPs degradation. These research trends and significant breakthroughs regarding Fe(II) are of crucial importance for promoting Fe(II) application in diverse fields.