Fenton-like degradation of sulfamethoxazole using Fe-based magnetic nanoparticles embedded into mesoporous carbon hybrid as an efficient catalyst

Fe-based magnetic nanoparticles (NPs) embedded into mesoporous carbon hybrid (Fe@MesoC) was successfully fabricated from Fe-based metal-organic framework (MIL-100(Fe)) through a pyrolysis method, which was for the first time proposed as a novel Fenton-like catalyst for the degradation of sulfamethoxazole (SMX). The catalytic activity of Fe@MesoC was systematically evaluated on the basis of several reaction parameters including initial pH, initial H2O2 concentration and temperature. Under the optimal conditions, the Fe@MesoC composite demonstrated a superior catalytic activity for decomposing SMX in the presence of H2O2, and it accomplished 100% SMX and 54.5% total organic carbon (TOC) conversion within 120 min. Such outstanding performance can be explained by the excellent enrichment ability of the outer mesoporous carbon matrix, the abundant active sites of the inner Fe-based NPs, as well as the possible synergistic effect between the two components. Moreover, the facile electrons transfer from Fe-0 to iron oxide in the inner Fe-based NPs could facilitate the reduction of Fe3+ to Fe2+ ( represents the iron species anchored to the surface of the catalyst) and further improve the generation of hydroxyl radicals. With the high structural stability and saturation magnetization, the Fe@MesoC composite can be easily recycled for three subsequent runs without significant activity loss. The possible catalytic mechanism and degradation pathways for SMX degradation induced by hydroxyl radicals in Fe@MesoC/H2O2 Fenton-like system were also tentatively proposed.