Three-dimensional flower-like magnetic CoFe-LDHs/CoFe2O4 composites activating peroxymonosulfate for high efficient degradation of aniline

Abstract

In this study, 3D flower-like magnetic CoFe-LDHs/CoFe₂O₄ was prepared by a facile urea hydrothermal method and utilized to activate peroxymonosulfate (PMS) for degrading aniline (AN). CoFe-LDHs/CoFe₂O₄ was systematically characterized to explore the relationship between its structure and catalytic performance. Compared with CoFe-LDHs synthesized by co-precipitation method, CoFe-LDHs/CoFe₂O₄ exhibited three dimensional structure and larger specific surface, which could increase the degradation efficiency of AN markedly. 96% of 10 mg L⁻¹ AN could be eliminated by 0.3 mM PMS and 50 mg L⁻¹ CoFe-LDHs/CoFe₂O₄ at initial pH 6 within 5 min and the total organic carbon (TOC) removal efficiency could be high to 52.8% in 30 min. CoFe-LDHs/CoFe₂O₄ can be separated by a magnet easily due to its magnetism, which makes it avoid secondary pollution and provide convenience. After recycling six times, the degradation efficiency still maintained at 92.6%. Besides, CoFe-LDHs/CoFe₂O₄/PMS can degrade AN in practical water samples effectively. In addition, the possible mechanism of CoFe-LDHs/CoFe₂O₄/PMS system for the degradation of AN was proposed. The radical scavenging experiments confirmed that SO₄·^-, HO· and O₂·^- were involved and SO₄·^- played a dominant role in the degradation of AN, and it was further proved by electron Paramagnetic Resonance (EPR) as well. Our findings can provide some new insights into the efficient and skillful design and application of heterogeneous catalyst for environmental remediation.