Degradation of methylene blue by a heterogeneous Fenton reaction catalyzed by FeCo2O4-N-C nanocomposites derived by ZIFs

Abstract

Rationally designing efficient nanomaterials for heterogeneous activation of peroxymonosulfate (PMS) is necessary for environmental remediation. Nitrogen-containing carbon/FeCo2O4 composites (FeCo2O4-N-C) were prepared by annealing the iron and cobalt in the ZIF-67 (Fe-Co-ZIF) precursor at different reaction temperatures. In the presence of PMS, 400 °C calcined nitrogen-containing carbon/FeCo2O4 composites (FeCo2O4-N-C-400) was used as catalyst for heterogeneous Fenton degradation of methylene blue (MB) and nearly 100% MB was removed within 10 min without pH adjustment. FeCo2O4-N-C-400 had excellent catalytic activity profiting from the uniform distribution of bimetals and nitrogen doping, which ensured the exposure of sites with high catalytic activity. Free radical quenching experiments showed that a large number of reactive oxygen species (SO4.- and .OH) were the cause of pollutant degradation. At the same time, the possible degradation mechanism of MB in FeCo2O4-N-C-400/PMS system was proposed. In addition, FeCo2O4-N-C-400 can still degrade 60% of MB after four cycles, which indicated that the catalyst had long-term catalytic durability and recyclability.