Magnetic COFs as catalyst for Fenton-like degradation of sulfamethazine

A novel magnetic covalent organic frameworks (COFs) (Fe2O3@COFs) composite was fabricated by restricting the growth of Fe2O3 in the nanoscale channel of COFs, which can be used as the Fenton-like catalyst for sulfamethazine (SMT) degradation in aqueous solution. The as-prepared catalyst had good crystallinity, porosity and nano-flower-shaped morphology, and the encapsulated Fe2O3 particles were well-distributed and restrained in the nano-channels of COFs. Furthermore, magnetic COFs could not only adsorb SMT, but also catalyze the Fenton-like degradation of SMT in the presence of H2O2 (about 100% of removal efficiency). Acidic condition (pH = 3) facilitated SMT degradation in Fe2O3@COFs/H2O2. system. In consecutive 5 cycles, the catalyst showed a good stability and reusability with a high removal efficiency (>96%), a good mineralization rate (about 35%)，and a very low Fe2+ leaching (below 0.1 mg L−1). Electron spin resonance (ESR) and quenching tests proved that hydroxyl radicals were the main reactive species generated in the Fe2O3@COFs/H2O2 system for the degradation of SMT. In conclusion, Fe2O3@COFs is a promising Fenton-like catalyst for the degradation of SMT and other toxic organic pollutants in water and wastewater.