Application of CuFeLDH–NCNT in ultrasound-assisted-Fenton-like process for removing ciprofloxacin from aqueous solutions

Abstract

In this study, the mesoporous material NCNT was prepared by treating carbon nanotubes (CNTs) with hydrazine and subsequently loaded with Cu–Fe-layered double hydroxide (CuFeLDH) to create a multiphase catalyst (CuFeLDH–NCNT). Its application as a multiphase catalyst was investigated in an ultrasound-assisted Fenton process for ciprofloxacin (CIP) degradation in aqueous solutions. In addition, the impacts of catalyst dosage, ultrasonic power, H2O2 dosage, and beginning pH on CIP removal efficiency were carefully evaluated to maximize the removal efficiency of CIP. The findings indicated that the elimination rate of the initial CIP concentration of 20 mg/L surpassed 94.66% after a mere 100 min, while the TOC degradation rate was 70.4%. The high breakdown rate was due to the synergistic action between the nanoparticles, H2O2, and ultrasonography. The degradation intermediates of CIP were examined, and putative degradation pathways and mechanisms were postulated. NCNT can effectively load and disseminate CuFeLDH while also providing reaction regions and catalytic active sites, accelerating the redox cycle of Fe2+/Fe3+, Cu+/Cu2+, and ensuring the proper operation of Fenton-like reactions. Furthermore, ultrasonography can expedite the transition of H2O2 to •OH, enhancing the reaction rate. The degradation intermediates of CIP were examined, and putative degradation pathways and mechanisms were postulated.