The Surface-mediated Fe(Ⅱ) Reduction System of Iron-pillared Montmorillonite for Efficient Removal of 2-Nitrophenol

Iron-pillared montmorillonite composite catalyst (FPMt) was successfully synthesized by optimizing the design of montmorillonite through the introduction of iron oxides and the calcination treatment. The structural and surface properties of FPMt samples were characterized with X-ray diffraction (XRD), thermogravimetric analysis (TG), TEM, FT-IR, N₂ adsorption and desorption isotherms, and 2-Nitrophenol (2-NP, 22 μmol/L) was used as a representative pollutant to identify the reduction catalytic activity of FPMt. The results showed that, compared to montmorillonite, the surface electron transport activity of FPMt was significantly improved due to the increase of adsorption sites of Fe(Ⅱ) and the corresponding reduction of acid sites on the surface of FPMt, significantly enhancing the reduction catalytic performance of the material. In addition to the solution pH and Fe(Ⅱ) concentration, the structural integrity of the catalyst and the crystallinity of hematite are important factors affecting the catalytic activity. Finally, a mediating mechanism for the significant increase in the reduction catalytic activity of complexed Fe(Ⅱ) on the surface of FPMt was proposed.