CuCoFe-LDHs activated sodium percarbonate (SPC) for the degradation of ciprofloxacin

Abstract

Sodium percarbonate (SPC) is widely used in Fenton-like technology for the organic wastewater treatment because of its low costs and convenient transportation. However, low utilization efficiency of hydrogen peroxide limits its application. In this work, a catalyst (CuCoFe-LDHs) was designed to activate SPC for degrading ciprofloxacin (CIP) effectively in heterogeneous Fenton system with higher H2O2 utilization rate (62 %) and higher stability (degradation rate of CIP decreased 5.6 % after five cycles). Since SPC was dissolved in water, H2O2 and CO32- were generated, and CO32- was transferred to HCO3- subsequently along with the variation of pH value. Plenty of •OH and •O2- was generated, and most of •OH was directly reacted with CIP. However, •O2-, was prone to react with HCO3- to form •CO3-, and then for degrading CIP. Compare with CuMgFe-LDHs catalyst, the electrochemical impedance spectroscopy (EIS) showed that CuCoFe-LDHs with stronger electron transfer ability. Therefore, the Co atom could facilitate the generation of specific free radical via enhancing electron transfer rate for the degradation of CIP in CuCoFe-LDHs. In summary, this study provides a cheap, recyclable, efficient and environmentally friendly wastewater treatment method for the degradation of refractory organic pollutants.