Enhanced degradation of ofloxacin by novel zero-valent iron particles@V2C MXene composites with efficient activation of peroxomonosulfate: Mechanistic insights and DFT calculations

The ubiquitous reliance on antibiotics in medicine, farming, and human beings has resulted in their excessive discharge into the environment, and inducing the emergence of resistance genes and drug-resistant pathogens. Therefore, it is especially important to discover an environmentally friendly and efficient way to degrade them. Herein, we loaded zero-valent iron particles onto V2C-based MXene (ZVIPs@V2C) to efficiently activate peroxomonosulfate (PMS) for the degradation of ofloxacin (OFL). The results showed that the OFL degradation reached 96.58 % within just 3 min with a kinetic constant of 0.9166 min-1. In addition, it also showed better degradation effect in pharmaceutical wastewater and agricultural wastewater. The excellent catalytic performance of ZVIPs@V2C can be attributed to the fact that V2C-based MXene (V2C) plays three important roles in the reaction system: 1) it inhibits the agglomeration of zero-valent iron particles (ZVIPs); 2) it mitigates the hydrolysis of ferric ions in the solution; and 3) it facilitates the reduction of Fe(III) during the reaction. In addition, quenching experiments and electron paramagnetic resonance (EPR) analyses showed that sulfate radicals (SO center dot 4-) and singlet oxygen (1O2) play dominant roles in the degradation process. Additionally, density functional theory (DFT) calculations were employed to probe the interaction sites between the materials and PMS, providing a theoretical foundation for the observed catalytic behavior. The possible degradation pathways of OFL were proposed based on DFT calculations and liquid chromatography-mass spectrometry (LC-MS) measurements. Toxicity analyses confirmed that most intermediates are more environmentally friendly than OFL, highlighting the environmental safety of this degradation approach. This study broadens the application of MXene in advanced oxidation processes and also provides novel strategies for degrading emerging organic pollutants by catalysts with excellent PMS activation capabilities.