Hydroxyl groups and vacancy defects modified Mo2C MXene as peroxymonosulfate activator for antibiotics degradation

Abstract

Antibiotic pollution poses significant threats to ecological health and food safety, highlighting the need for effective pollution control strategies. A novel Mo₂C MXene-OH&V_Mo (hydroxyl groups and Mo vacancy defects modified Mo₂C MXene) was developed through etching and hydrothermal methods, which facilitated the construction of a degradation system utilizing peroxymonosulfate for antibiotics degradation. The MXene-OH&V_Mo demonstrated enhanced adsorption of HSO₅⁻, achieving an adsorption energy of -1.73 eV, which is superior to that of unmodified Mo₂C MXene (-0.42 eV). The activation of HSO₅^– by Mo vacancies involved the transfer of 0.63 e, leading to the generation of reactive oxygen species (^•OH, ¹O₂, SO₄^•− and O₂^•−) responsible for degrading three antibiotics with degradation percentages exceeding 97.00%. The presence of hydroxyl groups further improved the activation efficiency of HSO₅⁻ by optimizing the electron arrangement of Mo₂C MXene-OH&V_Mo. The extent of antibiotic degradation was influenced by atomic charge distribution. Additionally, Mo₂C MXene-OH&V_Mo exhibited remarkable repeatability, maintaining degradation percentages above 88.00% after four cycles. The condensed Fukui function was utilized to identify highly active sites of antibiotics, and combined with degradation products analyzed by HPLC-MS/MS, commonalities in detailed degradation pathways were revealed. Furthermore, the products were found to pose negligible toxicity risks to ecological receptors and humans. These findings hold significant implications for the future use of MXene-based catalyst advanced oxidation technology in the treatment of organic pollutants and offer sustainable solutions for environmental remediation. Insights into the development of new catalysts through surface modification engineering were also presented in this study.