Fast and complete removal of quinolones from actual water matrices by activated peroxymonocarbonate via magnetic Co–Cu in carbon nanofibers
摘要
The extensive use of quinolones leads to serious residues in different water matrices and consequent ecological risks. Magnetic Co–Cu incorporated in-situ in carbon nanofibers (Co–Cu/CNFs) were prepared for peroxymonocarbonate (PMC) activation during quinolone degradation. The as-synthesized nanocomposites exhibited a high aspect ratio, large specific surface area (283.6 m2·g−1), encapsulated Co and Cu nanoparticles and magnetic response (6.2 emu·g−1). Complete pefloxacin degradation can be achieved in 8 min in the Co–Cu/CNFs activated PMC system, and six other commonly used and detected quinolones can also be completely removed in approximately half an hour. Furthermore, ciprofloxacin can be completely decomposed within 50 min in different actual water matrices. The remarkable catalytic activities of Co–Cu/CNFs might be attributed to the increasing conductivity and electron transfer capability according to electrochemical impedance spectroscopy. The Co–Cu/CNFs activated PMC system is superior to other counterpart activated peroxide systems in terms of faster removal rates, less leakage of metal ions and greater proportions of heterogeneous catalytic reactions. Singlet oxygen was the primary contributor to ciprofloxacin degradation, followed by hydroxyl, carbonate and superoxide anion radicals. The pharmacophores of 26 ciprofloxacin transformation products were converted by reactive species, including 81% pharmacophore removal which is beneficial for subsequent natural attenuation or biological treatment.
Graphic abstract