Well-dispersed zero-valent iron nanoparticles within nitrogen-doped mesoporous carbon: One-pot synthesis, characterization, and catalytic activity for acid red 18 treatment

Abstract

The current research suggests an innovative approach to synthesize zero-valent iron nanoparticles (nZVI) embedded within nitrogen-doped mesoporous carbon (NMC) by pyrolyzing a mixture containing F127 as a soft template, Fe(NO₃)₃ as an iron precursor, resol as a carbon source, and dicyandiamide as a nitrogen source. The resulting material (nZVI/NMC) exhibited a well-defined mesostructure with a large mesopore size of 7.6 nm, a high specific surface area of 361 m²/g, and a large total pore volume of 0.41 cm³/g. In addition, nZVI with an average diameter of 17 ± 3 nm was evenly distributed within the NMC framework. With 16.3 wt% Fe loading, nZVI/NMC possessed a strong saturation magnetization of 25.4 emu/g, enabling rapid magnetic separation. Subsequently, nZVI/NMC was investigated as a catalyst for acid red 18 (AR18) treatment by H₂O₂. At pH 3.0 and 200 mg/L H₂O₂, 1.00 g/L nZVI/NMC completely removed 50 mg/L AR18 within 30 min. Moreover, the catalyst maintained excellent reusability with negligible iron leaching over four successive runs. With its high catalytic activity, stability, and facile magnetic recoverability, nZVI/NMC demonstrates significant promise as a rapid and reusable catalyst for treatment of organic pollutants in wastewater.