Degradation of methylene blue with magnetic Co-doped Fe₃O₄@FeOOH nanocomposites as heterogeneous catalysts of peroxymonosulfate

Authors

• Kai Wang, Sichuan University, Chengdu
• Yi Yang, University of Nebraska-LincolnFollow
• Tian C. Zhang, Engineering & Research Incorporation Limited, Wuhan,
• Ying Liang, Sichuan University, ChengduFollow
• Qingguo Wang, Sichuan University, ChengduFollow

ORCID IDs

Kai Wang http://orcid.org/0000-0002-3810-4230

Document Type

Article

Date of this Version

2019

Citation

RSC Adv., 2019, 9, 17664

DOI: 10.1039/c9ra01671f

Comments

CC-BY-NC

Abstract

Magnetic Co-doped Fe₃O₄@FeOOH nanocomposites were prepared in one step using the hydrothermal synthesis process for catalyzing peroxymonosulfate (PMS) to degrade refractory methylene blue (MB) at a wide pH range (3.0–10.0). The catalysts' physiochemical properties were characterized by different equipment; Fe³⁺/Fe²⁺ and Co³⁺/Co²⁺ were confirmed to coexist in the nanocomposite by X-ray photoelectron spectroscopy. The nanocomposite effectively catalyzed PMS's decoloration (99.2%) and mineralization (64.7%) of MB. The formation of Co/Fe–OH complexes at the surface of nanoparticles was proposed to facilitate heterogeneous PMS activation. Compared with the observation for Fe₃O₄@FeOOH, the pseudo-first-order reaction constant was enhanced by 36 times due to Co substitution (0.1620 min^–1 vs. 0.0045 min^–1), which was assigned to the redox recycle of Fe³⁺/Fe²⁺ and Co³⁺/Co²⁺ in Co-doped Fe³O₄@FeOOH. Besides, the catalyst could be easily reused by magnetic separation and exhibited relatively long-term stability.