Cobalt-doped biogenic manganese oxides for enhanced tetracycline degradation by activation of peroxymonosulfate

BACKGROUND Tetracycline (TC) residues in water and soil have received wide attention due to their adverse effects on human health and ecosystem. Layer-structured biogenic manganese oxides (BMOs) could be obtained from fungi Pleosporales sp. Y-5 culture. Cobalt doping into BMOs (Co-BMOs) was conducted by a facile impregnation-calcination method to eliminate TC residues through activation of peroxymonosulfate (PMS). RESULTS The TC in aqueous solution could be nearly completely removed in about 10 minutes under the optimal condition ([TC] = 50 mg L-1, [catalyst] = 0.2 g L-1, [PMS] = 0.4 g L-1, 25 degrees C). The electron paramagnetic resonance (EPR) identified the coexistence of SO4-center dot and OH center dot during PMS activation. The Co-BMOs catalyst remained great catalytic activity after five runs. Possible mechanism of PMS activation and TC degradation pathway were proposed. Preliminary biological toxicity test using green algae Chlorella vulgaris (FACHB-8) as ecological indicator confirmed that TC degradation solution was less toxic than the original solution. CONCLUSION This study demonstrated high catalytic activity and stability of Co-BMOs for degradation of TC by PMS activation. The Co-BMOs/PMS system is helpful in new efforts for TC degradation without generation of more toxic intermediates. (c) 2018 Society of Chemical Industry