A low-cost magnetic catalyst (MnFe2O4) for ciprofloxacin degradation via periodate activation: The synergistic effect of Mn and Fe

The treatment of water pollution caused by excessive usage of antibiotics has been widely concerned. Periodate (PI)-oxidation method poses a good application prospect for antibiotic degradation with a stable solid oxidant and excellent degradation efficiency. In this study, manganese ferrite (MnFe2O4) with superparamagnetic property, low ion leaching, and outstanding activation performance was chosen to active PI to remove cipro-floxacin (CIP) for the first time. And MnFe2O4/PI system could achieve 98.8% removal efficiency of 10 mg/L CIP in 90 min (pH = 5.4, 0.3 g/L MnFe2O4, 0.2 g/L PI). With the conversion of Fe(II)/Fe(III) and Mn(II)/Mn(III)/Mn (IV), singlet oxygen (1O2), iodate radical (IO3 & BULL;), and superoxide radical (O2 & BULL;) were formed as the primary active substances to remove CIP. Meanwhile, the redox cycle of Fe(III)/Fe(II) (0.77 V) and Mn(IV)/Mn(III) (0.15 V) accelerated the process of CIP degradation. Almost 90% of CIP could be removed by MnFe2O4/PI system after 5th run, showing the excellent stability of MnFe2O4 to activate PI. Besides, MnFe2O4/PI system showed tolerance to different background water and selectivity to different antibiotics. This work presents a novel strategy to inte-grate MnFe2O4 with PI for antibiotic-polluted water treatment.

Automated summary

In this study, manganese ferrite (MnFe2O4) was used to activate periodate (PI) to remove ciprofloxacin (CIP) from water, achieving a high removal efficiency. Fe(II)/Fe(III) and Mn(II)/Mn(III)/Mn(IV) conversions facilitated the degradation of CIP, forming singlet oxygen (1O2), iodate radical (IO3•), and superoxide radical (O2•−) as primary active substances. The MnFe2O4/PI system showed good tolerance to different water sources and selectivity towards different antibiotics.