Ti3C2T x MXene: Colloidal Behavior and Combined Antibacterial Effects with Common Antibiotics─Implications for the Remediation of Antibiotic-Contaminated Water

Ti3C2Tx MXene has emerged as a promising nanomaterial for environmental remediation, yet its interfacial behavior with coexisting pollutants remains complex. We investigated the interactions between Ti3C2Tx MXene and three antibiotics (erythromycin (H), chloramphenicol (L), and gentamicin sulfate (Q)) as well as their combined antibacterial effects, which are regulated by multiple abiotic and biotic factors. Ti3C2Tx MXene exhibited instability in antibiotic solutions and readily aggregated with Q; Q concentrations >5 mg/L triggered visible sedimentation within 3 h in bacteria-containing systems, altering MXene’s particle size and surface zeta potential. The combination of 20 mg/L MXene and ≥5 mg/L Q achieved a killing efficiency >95% against Staphylococcus aureus within 3 h. This enhancement may be associated with increased bacterial adsorption by larger MXene aggregates; however, the independent contribution of partial surface oxidation was not isolated. X-ray photoelectron spectroscopy (XPS) indicated changes in surface oxygen environments and carbon-containing groups after Q exposure. The C 1s components near 286.1 and 288.4 eV were tentatively associated with C–O/C–N and O–C=O environments, respectively. Changes in N 1s features did not confirm formation of −NHOH or −NO2. These results characterize interfacial functional-group evolution and chemical-state changes relevant to the behavior of MXene-based materials in antibiotic-contaminated water.