One-pot green synthesis of Zero-Valent iron particles supported on N-Doped porous carbon for efficient removal of organic pollutants via Persulfate Activation: Low iron leaching and degradation mechanism

In this work, zero-valent iron particles supported on nitrogen doped porous carbon (Fe-NPC) was successfully prepared by a green and convenient one-pot method through pyrolysis. In Fe-NPC/PS system, 96.44% orange II (OGII) was almost removed within 35 min, which was much higher than NPC and Fe-PC of 53.27% and 54.67%, respectively. Factors influencing the degradation process of OGII were investigated, including PS concentration, catalyst dosage, initial pH and ions disturbance. The radical quenching studies, electron paramagnetic resonance (EPR) measurements and chronoamperometry experiments verified the degradation mechanism of OGII in Fe-NPC/PS system included both radical and non-radical pathways in which •HO and SO4-· were the dominant active radicals and electron transfer was involved. Fe-NPC exhibited excellent tolerance toward a wide pH conditions with only 88 µg/L iron leaching in initial pH of 3.1, which was much lower than literature reported. The low iron leaching of Fe-NPC was attributed to the protection of carbon matrix and doped nitrogen in catalyst. Moreover, the surface CO group of the catalyst contributed to better performance in alkaline system. Furthermore, the supported iron species introduced magnetism into the catalyst for easily separation. The Fe-NPC/PS system also exhibited high removal efficiencies for Congo red (CR), Reactive blue 19 (RB 19), 4-Nitrophenol (4-NP) and tetracycline (TC). These results provided a sight for economically and efficiently fabricating stable iron based nitrogen doped porous carbon catalyst for water contaminant degradation.