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

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.