Utilization of oxidized Fe-based metallic glass as efficient catalysts for wastewater remediation

Fe-based metallic glass (Fe-based MG) ribbons are susceptible to surface oxidation during long-term service, resulting in degraded magnetic and catalytic properties. In this work, a rapid and cost-effective strategy, termed Selective Etching and Ion Exchange (SEIE), was applied to restore the catalytic activity of oxidized Fe-based MG ribbons. Fe 73.5 Si 13.5 B 9 Cu 1 Nb 3 ribbons were thermally oxidized at 200 °C for 30–240 min to simulate varying degrees of aging after service, followed by surface cleaning and SEIE activation. The activated Fe-based MG ribbons exhibited a first-order rate constant ( k obs ) of 2.37 min −1 for degrading 20 mg/L acid orange 7 (AO7), which is an order of magnitude higher than that of the pristine ribbons. Microstructural characterization revealed the formation of Cu clusters with two distinct morphologies generated by ion exchange, which induced a galvanic coupling effect, significantly enhancing hydroxyl radical (·OH) generation and catalytic degradation. However, excessive Cu deposition impeded Fe-H 2 O 2 interactions, reducing catalytic activity. The activated Fe-based MG ribbons maintained 70 % higher k obs values than the pristine ribbon after 10 degradation cycles, and exhibited excellent performance for phenol degradation ( k obs =0.417 min −1 ). This study demonstrates a sustainable and efficient surface-activation approach for utilizing oxidized Fe-based MGs, offering both environmental and economic benefits.