The Structural Evolution of Bimetallic Fe/Ag Mediated by Montmorillonite and Its Effect on Triclosan in the Environment

Montmorillonite (Mont) is a natural two-dimensional material with a 2:1 layered silicate crystal structure. It possesses abundant surface groups, cation exchange capacity, and adsorption performance. In addition, it has other advantages such as abundant reserves, environmental friendliness, strong mechanical stability, and a large specific surface area. As such, it shows excellent potential for application in environmental remediation. In the following paper, we focus on the removal of TCS (triclosan) from an aqueous environment by utilizing montmorillonite-supported bimetallic Fe/Ag particles. We use scanning electron microscopy, X-ray diffraction patterns, Fourier-transform infrared spectra, and specific surface area to analyze the structure, morphology, and composition of these nanocomposites. The effects of the pH, different materials, contact time, and different initial concentrations on the degradation efficiency of TCS were studied systematically. Based on the results of our study, montmorillonite-supported bimetallic Fe/Ag nanoparticles (Fe/Ag-Mont) should be categorized as a type of mesoporous material of high uniformity because the pore size of all its catalysts ranges from 10 to 20 nm, and they are well-distributed. The Si-O stretching vibrations of montmorillonite can be changed by adding Fe/Ag. We found that Fe or Ag combined with -O to form a new bond and interacted with Si-O, and the incorporation of Fe/Ag-Mont nanoparticles removed TCS with better reduction rates. By enhancing reduction capacity, the pH was below 4 due to H• species generation by Fe/Ag. H• was the main factor enhancing the redox reaction in reducing TCS. The pH controlled the competition between Fe corrosion and silver formation, which enabled the system to self-regulate. In addition, this study provided a suitable method of efficiently synthesizing clay-supported bimetallic nano-system materials for reduction.