Carbon fiber-assisted iron carbide nanoparticles as an efficient catalyst via peroxymonosulfate activation for organic contaminant removal

The development of efficient and environment-benign catalytic materials to activate peroxymonosulfate (PMS) for refractory pollutant removal has been considered as an attractive yet challenging topic in the field of wastewater treatment. Herein, carbon fiber-assisted iron carbide (Fe3C@CFs) was innovatively prepared by a hydrothermal and calcination method. Fe3C@CFs could activate PMS and remove the pollutant Acid Red 1 (AR1) up to 97.3%, and even the rate constant was 12.4 times higher than that of Fe3C. The leaching of iron ions was only 0.002 ppm, which was extremely lower than the European standard. Furthermore, Fe3C@CFs still exhibited a favorable catalytic performance after 4 cycles. The catalytic mechanism was investigated by a hybrid method of various radical scavengers combined with electron spin resonance, suggesting that 1O2 served as the main reaction oxidation species rather than ˙OH or SO4˙− during the catalytic process, different from most of the reported radical paths for activating PMS. In addition, Fe3C@CFs possessed wide pH adaptability (3–10) and relatively low activation energy (24.47 kJ mol−1) for AR1 removal. These findings pave a promising avenue to develop highly efficient and eco-friendly catalytic materials for environmental remediation.