Recent advances in sulfidized nanoscale zero-valent iron materials for environmental remediation and challenges

Over the past decade, sulfidized nanoscale zero-valent iron (S-nZVI) has been developed as a promising tool for the remediation of contaminated soil, sediment, and water. Although most studies have focused on applying S-nZVI for clean-up purposes, there is still a lack of systematic summary and discussion from its synthesis, application, to toxicity assessment. This review firstly summarized and compared the properties of S-nZVI synthesized from one-step and two-step synthesis methods, and the modification protocols for obtaining better stability and reactivity. In the context of environmental remediation, this review outlined an update on the latest development of S-nZVI for removal of heavy metals, organic pollutants, antibiotic resistance genes (ARGs), and antibiotic resistant bacteria (ARB) and also discussed the underlying removal mechanisms. Environmental factors affecting the remediation performance of S-nZVI (e.g., humic acid, coexisting ions, S/Fe molar ratio, pH, and oxygen condition) were highlighted. Besides, the application potential of S-nZVI in advanced oxidation processes (AOP), especially in activating persulfate, was also evaluated. The toxicity impacts of S-nZVI on the environmental microorganism were described. Finally, the future challenges and remaining restrains to be resolved for better applicability of S-nZVI are also proposed. This review could provide guidance for the environmental remediation with S-nZVI-based technology from theoretical basis and practical perspectives.

Automated summary

This review summarizes the synthesis, application, toxicity assessment, and future challenges of sulfidized nanoscale zero-valent iron (S-nZVI) in the remediation of contaminated soil, sediment, and water. It discusses the properties of S-nZVI synthesized from different methods, the modification protocols for better stability and reactivity, and its applications in removing heavy metals, organic pollutants, antibiotic resistance genes (ARGs), and antibiotic resistant bacteria (ARB). The review highlights the environmental factors affecting the performance of S-nZVI and evaluates its potential in activating persulfate in advanced oxidation processes (AOP). It also describes the toxicity impacts of S-nZVI on environmental microorganisms.