Peroxydisulfate activation by enhanced catalytic activity of CoFe2O4 anchored on activated carbon: A new sulfate radical-based oxidation study on the Cefixime degradation

This work focused mainly on anchoring cobalt ferrite (CF) nanoparticles onto the surfaces of activated carbon (AC) for preparation of recoverable AC@CF composite as a heterogeneous peroxydisulfate (PDS) activator towards cefixime (CEF) degradation. Catalytic-mediated PDS activation potential of CF nanoparticles was significantly enhanced after anchoring onto the AC surfaces, indicating the efficient role of AC in inhibition of CF agglomeration. AC@CF/PDS system could achieve the complete degradation of CEF (with the reaction rate constant of 0.11 min(-1)) and 63.7% mineralization within only 40 min in the presence of 0.4 g/L catalyst and 3.0 mM PDS at pH 7.0. Comparative tests verified a strong synergistic effect (with synergy factor value of 2.75) between AC@CF and PDS towards CEF decontamination. The possible mechanisms of PDS activation, the generation of reactive species and the degradation pathway were proposed and discussed in details. AC@CF showed an excellent recyclability and stability in terms of CEF and TOC elimination and the removal efficiencies of 82.4 and 46.7% were attained in the fifth cycle, respectively. The quantity of leached metal ions from the catalyst surface to the reaction solution in each studied cycle was approximately < 2 % mass of used AC@CF . Based on the reactive species capture tests, the importance of their contribution in degradation process was in order of: SO4 center dot- > HO center dot > O-2(center dot-). This work provides the key role of AC in improving the CF catalytic activity for activating PDS and efficient degradation of antibiotics from contaminated-water resources with high performance and safe application.

Automated summary

This work focuses on anchoring cobalt ferrite nanoparticles onto activated carbon surfaces to prepare a recoverable AC@CF composite. The composite exhibits excellent catalytic activity in activating peroxydisulfate (PDS) for cefixime (CEF) degradation, achieving complete degradation and significant mineralization within a short time. The study also explores the synergistic effect between AC@CF and PDS, and proposes mechanisms and pathways for PDS activation and CEF degradation. The AC@CF composite demonstrates recyclability, stability, and low leaching of metal ions. Reactive species capture tests reveal the importance of sulfate radicals in the degradation process. The research provides valuable insights and applications for improving the catalytic activity of cobalt ferrite and the efficient degradation of antibiotics in contaminated water sources.