Activation of peroxymonosulfate by Fe0@Fe3O4 core-shell nanowires for sulfate radical generation: Electron transfer and transformation products

Nanoscale zero-valent iron (nZVI) is highly promising for oxidative removal of micropollutants by initiating advanced oxidation processes , but its vulnerability to deactivation due to the surface oxidation is challenging. In this study, we propose Fe 0 @Fe 3 O 4 core–shell nanowires (CSNWs) as a novel activator to generate radicals for atrazine, a representative micropollutant, degradation via the activation of peroxymonosulfate (PMS). Fe 0 @Fe 3 O 4 CSNWs with a shell thickness of around 5 nm were synthesized using a facile chemical reduction approach and were comprehensively characterized using a series of surface sensitive techniques. The results showed that the Fe 0 @Fe 3 O 4 CSNW had great reactivity for atrazine degradation via the activation of PMS; near complete degradation of atrazine was achieved after reaction for only 2 min. Under identical conditions, the pseudo-first order rate constant with Fe 0 @Fe 3 O 4 was more than 36 times greater than that with nano Fe 3 O 4 . The surface activation of PMS contributed only a small proportion to the overall degradation. Instead, the iron released from Fe 0 @Fe 3 O 4 CSNWs primarily activated PMS to generate S O 4 ∙ - that degraded atrazine. The Fe 0 @Fe 3 O 4 CSNWs were stable and no deactivation was observed after exposing Fe 0 @Fe 3 O 4 CSNWs to air for 3 months. The results from this study demonstrate a stable nZVI for oxidative removal of organic contaminants.