One-pot fabrication of sludge-derived magnetic Fe,N-codoped carbon catalysts for peroxymonosulfate-induced elimination of phenolic contaminants

• Published in: Chemosphere (Oxford) 2020-06, Vol.248, p.126076-126076, Article 126076
• Main Authors: Wang, Jing, Kou, Lidong, Zhao, Liang, Duan, Wenjie
• Format: Article
• Language: English
• Subjects: Bisphenol A degradation; Carbon - chemistry; Catalysis; Iron - chemistry; Magnetic Fe,N-codoped carbon catalyst; Magnetic Phenomena; Models, Theoretical; Nitrogen - chemistry; Oxidation-Reduction; Peroxides - chemistry; Peroxymonosulfate; Phenols - analysis; Recycling; Sewage - chemistry; Sludge reutilization; Waste Water - chemistry; Water Pollutants, Chemical - analysis; Water Purification - methods
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2020.126076

The use of waste sludge as a precursor of catalysts for environmental applications has been encouraged during the past few years. In this study, a series of magnetic Fe,N-codoped carbon catalysts (UBC-x) were successfully prepared by a facile one-pot pyrolysis method using Fe-rich sludge and N-rich urea as the raw materials. By carefully controlling the mass ratio of urea/dry sludge (x = 0–3), a significant amount of N (1–10 mass%) were incorporated, and the UBC-x catalysts, especially UBC-0.5 and UBC-0.75, could be imparted with high catalytic activity, convenient magnetic separation and high recycle stability. Phenolic contaminants like phenol and bisphenol A (BPA) could be nearly completely removed through peroxymonosulfate (PMS)-induced degradation by using UBC-x as the catalysts under a wide pH range (2–11) and with the co-existence of water constituents (chloride Cl− and sodium humate NaH, 0–50 mM). Among the several reactive oxidative species (ROS), singlet oxygen (1O2) was deemed as the main reactive species responsible for BPA degradation. Both Fe and N active sites contributed to the high catalytic activity of UBC-x, and their coordination made the catalysts rather stable with no significant Fe leaching under a wide pH range. Therefore, after an easy magnetic separation, the UBC-x could be recycled and reused efficiently in another BPA removal cycle. The as-synthesized magnetic Fe,N-codoped carbon catalysts provided a new route for sludge reutilization and showed potential applications in wastewater treatment. [Display omitted] •Magnetic Fe,N-codoped catalysts were prepared by pyrolysis of sludge and urea.•Magnetic and catalytic activity of catalysts depended on urea/sludge mass ratio.•BPA degradation by catalyst/PMS was tolerant to pH and water constituents.•Both Fe & N contributed to high activity and stability, no Fe leaching was found.•1O2 was deemed as the main ROS responsible for BPA removal.