Research Progress on Modification Strategies of Nanoscale Zero-Valent Iron and Its Application in the Removal of Organic Pollutants.

Nanoscale zero-valent iron (nZVI) exhibits great potential in the field of organic pollutant remediation due to its strong reducibility, high specific surface area and unique core-shell structure. However, pristine nZVI has inherent drawbacks including severe particle aggregation, surface passivation and poor electron selectivity, which greatly restrict its practical remediation performance. To improve the reactivity of nZVI, researchers have developed multiple modification approaches that significantly improve the dispersibility, stability and reactivity of nZVI. This review summarizes the main nZVI modification strategies, including metal modification, surface coating, carrier loading, sulfidation modification and biological integration. The advantages and limitations of each modification method are compared. Furthermore, the underlying removal mechanisms of modified nZVI toward typical organic pollutants are elaborated, covering direct reduction, advanced oxidation and synergistic degradation pathways. Key factors governing the degradation efficiency of modified nZVI are subsequently analyzed. Finally, existing bottlenecks for practical implementation and future research perspectives are proposed.