Enhancing the activation of persulfate using nitrogen-doped carbon materials in the electric field for the effective removal of -nitrophenol

• Published in: RSC advances Vol. 11; no. 6; pp. 383 - 3815
• Main Authors: Tang, Mengdi, Zhang, Yonggang
• Format: Journal Article
• Published: 25.11.2021
• ISSN: 2046-2069
• DOI: 10.1039/d1ra06691a

Degradation of nonbiodegradable organic compounds into harmless substances is one of the main challenges in environmental protection. Electrically-activated persulfate process has served as an efficient advanced oxidation process (AOP) to degrade organic compounds. In this study, we synthesized three nitrogen-doped carbon materials, namely, nitrogen-doped activated carbon plus graphene (NC), and nitrogen-doped activated carbon (NAC), nitrogen-doped graphene (NGE), and three nitrogen-doped carbon material-graphite felt (GF) cathodes. The three nitrogen-doped carbon materials (NC, NGE, NAC) were characterized using X-ray diffraction, Raman spectroscopy, X-ray electron spectroscopy, and nitrogen desorption-adsorption. The electron spin resonance technique was used to identify the presence of hydroxyl radicals (&z.rad;OH), sulfate radicals (SO 4 &z.rad; − ) and singlet oxygen ( 1 O 2 ) species. The results showed that NC was more conducive for the production of free radicals. In addition, we applied NC-GF to an electro-activated persulfate system with the degradation of p -nitrophenol and investigated its performance for contaminant degradation under different conditions. In general, the nitrogen-doped carbon electrode electro-activated persulfate process is a promising way to treat organic pollutants in wastewater. In the process of electro-activation of PDS by carbon cathode, PNP was removed from water mainly through SO 4 &z.rad; − produced by cathode, &z.rad;OH and 1 O 2 produced indirectly, direct electron transfer and non-free radical oxidation of anode.