Cu-Co binary metal-organic framework nanosheets for highly efficient degradation of norfloxacin using the Fenton-like process

Abstract

Efficient catalyst development for hydrogen peroxide activation is crucial in advanced oxidation processes (AOPs) technology. In this study, we successfully synthesized a bimetallic organic framework incorporating Cu-Co MOF nanosheets via a one-pot strategy. The subsequent Cu-Co MOF nanosheets demonstrated outstanding oxidative activity, achieving a remarkable 95.37 % removal of norfloxacin (NOR), surpassing the efficacy of Cu MOF/H2O2 or Co MOF/H2O2 nanosheets alone by 1.34 and 2.59 times, respectively. Density functional theory (DFT) calculations revealed that the bimetallic MOF nanosheets: firstly, enhanced optimization of the adsorption energy for H2O2 activation; and secondly, facilitated the cleavage of the O–O bond in H2O2. Furthermore, electrochemical impedance spectroscopy (EIS) analysis demonstrated a significant improvement in interfacial electron transfer once dual-reaction centers were introduced into the Cu-Co MOF nanosheets. Electron paramagnetic resonance analysis and quenching tests confirmed that 1O2, ·O2− and ·OH were involved in NOR degradation. Reasonable NOR degradation pathways were proposed by analysing the results of LC-MS and DFT calculations. Moreover, the synthesized nanosheets exhibited excellent reusability, with more than 90.00 % NOR removal achieved using the Cu-Co MOF nanosheets/H2O2 system after reuse on 3 occasions. These findings underscore the effectiveness of bimetallic MOF construction in developing highly efficient MOF-based Fenton-like catalysts. Also highlighted here is the promising role of Cu-Co MOF nanosheets in wastewater treatment, particularly for the removal of antibiotics.