Effect of Etching Condition on Nanoporous Structure and Methyl Orange Decomposition of Fe-Si-B Metallic Glass

Abstract

As an efficient advanced oxidation process, the Fenton-like reaction provides a promising way toward the degradation of organic pollutants; thus, the development of a highly efficient heterogeneous catalyst is of great significance. Herein, the chemical etching behavior of Fe-Si-B metallic glass (MG) ribbons in a dilute HF solution is studied by varying the etching time. Based on this, the uniform nanoporous (NP) structures are successfully fabricated. The Fe-Si-B MG ribbons after etching for 30, 60, and 90 min still maintain an amorphous structure and possess much larger specific surface areas than untreated Fe-Si-B ribbons. The thicknesses of their nanoporous structures, with a pore size range of tens to hundreds of nanometers, are about 92.0, 180.5, and 223.4 nm, respectively. The formation of the nanoporous structure probably follows the pitting corrosion mechanism, mainly referring to the generation of corrosion pits due to the selective leaching of Si and B and pore growth and integration owing to the selective corrosion of Fe. The Fenton-like system of NPFe/H2O2 exhibits enhanced degradation performance toward methyl orange (MO), primarily due to the high intrinsic catalytic activity of the amorphous structure and the large specific surface areas of nanoporous structures, indicating the great potential application of NPFe in wastewater treatments. The mechanism analysis shows that MO degradation mainly contains two sub-processes: the heterogeneous reaction on the catalyst surface and the homogeneous reaction in MO solution, which exhibit a strong synergistic effect with excellent degradation performance.

Keywords

• nanoporous structure
• chemical etching
• wastewater treatment
• degradability
• Fenton-like reaction