Efficient removal of levofloxacin by iron (II) phthalocyanine/g-C3N4 activated peroxymonosulfate under high salinity conditions: Role of high-valent iron-oxo species

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 470; p. 144038
• Main Authors: Wang, Yanbin, Shi, Zezhou, Shen, Haibo, Xing, Qiushuang, Pi, Yunqing
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-08-2023
• Subjects: High salinity wastewater; High-valent iron-oxo species; Iron (II) phthalocyanine; Organic pollutants; Peroxymonosulfate; High-valent iron-oxo species; Organic pollutants; High salinity wastewater; Peroxymonosulfate; Iron (II) phthalocyanine
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.144038

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•Iron phthalocyanine-supported g-C3N4 (FePc/CN) composite was successfully synthesized.•The FePc/CN showed high utilization for PMS and efficient elimination of organic contaminants.•The removal of LVF was mainly ascribed to the high-valent iron-oxo species (FeIVO2+).•The oxidation system exhibited excellent selective oxidation and high tolerance to high salinity conditions.•The FePc/CN catalyst presented good chemical stability and reusability.
Efficient and selective removal of organic contaminants using traditional radical-dominated Advanced Oxidation Processes (AOPs) in complex environmental matrices is challenging, especially under high salinity conditions. This study proposes an alternative approach using iron (II) phthalocyanine-supported g-C3N4 composite (FePc/CN) as a peroxymonosulfate (PMS) activator to efficiently remove organic contaminants. The FePc/CN-PMS process was selective towards the elimination of various organic contaminants, and those compounds with lower ionization potential value can be effectively degraded after reaction for 10 min. Results from radical quenching experiments, electron spin resonance (ESR), and PMSO chemical probe indicated that the dominant active species in the FePc/CN-PMS process are high-valent iron-oxo species (FeIVO2+), rather than the long-recognized SO4•− and •OH radical. A total of 22 intermediate products resulting from the degradation of levofloxacin (LVF) were identified by LC-MS. Additionally, two degradation pathways of LVF were proposed, with the piperazine ring of LVF being the primary site of degradation. The 5%FePc/CN-PMS system demonstrates resistance to ubiquitous inorganic anions and dissolved organic matter (DOM) in an aquatic environment, enabling efficient removal of (LVF) even under high salinity conditions. Furthermore, the 5%FePc/CN catalyst exhibits good chemical stability and reusability, making it a viable option for practical water remediation.