Advance of Sulfidated Nanoscale Zero-Valent Iron: Synthesis, Properties and Environmental Application

Abstract

Nanoscale zero-valent iron (nZVI) is one of the most extensively studied materials in the field of water environment remediation. But the limitations of easy agglomeration, oxidation and poor electronic selectivity restrict its practical application. After the sulfidation on the surface of nZVI, the sulfidated nanoscale zero-valent iron (S-nZVI) can be formed, which can not only enhance the dispersion and stability, but also improve the electronic selectivity, thus becoming the hot spot recently. The synthesis methods, physiochemical properties and practical performances of S-nZVI are discussed detailedly in this review. Firstly, the effects of synthesis methods on the physiochemical properties of S-nZVI are summarized, which focus on adjusting the synthesis conditions (sulfidation sequence, sulfur precursors, S/Fe, etc.) to change the microstructure and chemical states of interface elements of S-nZVI (actual S/Fe, sulfur distribution, FeSx morphologies, etc.). And then the macro-properties (hydrophilicity/hydrophobicity, hydrogen evolution, conductivity, etc.) will be altered correspondingly, which will cause the directional removal of organic pollutants and heavy metal pollutants. Additionally, the research progress of S-nZVI in the removal of chlorinated hydrocarbons, antibiotics, nitrobenzene organics and heavy metals are discussed concretely and the future research directions are analyzed as well.

Removal mechanism of Pb(ii) from soil by biochar-supported nanoscale zero-valent iron composite materials

“…This suggests a potential chemical transformation between the heavy metal ions and BC-nZVI, emphasizing the material's affinity for Pb(II). 40 The positive value of DS 0 usually arises from the dehydration of metal ions and the breaking of hydration shells, partially explaining the positive value of DH 0 , suggesting that the dehydration of Pb(II) and metal ions involves heat absorption. 41 Additionally, the data also show that jDH 0 j < jTDS 0 j, suggesting that the adsorption process is primarily controlled by entropy rather than enthalpy.…”