Ytterbium-doped bismuth-based metal-organic framework enables synergistic adsorption and photocatalysis for efficient oxytetracycline removal

The widespread contamination of water resources by oxytetracycline (OTC) originating from medical and agricultural applications has necessitated the development of efficient remediation technologies. This study addresses this challenge by developing a ytterbium-doped bismuth-based metal-organic framework (Yb/Bi-MOF) through solvothermal synthesis, which integrates adsorption and photocatalytic degradation to achieve enhanced OTC removal. Yb-doped Bi-MOF composite (Yb 3 /Bi-MOF) demonstrating exceptional performance by achieving an adsorption capacity of 34.71 mg/g and 91.31 % photocatalytic degradation efficiency under xenon lamp illumination, significantly surpassing pristine Bi-MOF. Comprehensive characterization using XRD, XPS, and UV-Vis DRS revealed that optimal Yb³⁺ doping effectively narrowed the band gap to 3.82 eV, enhanced light absorption, and facilitated charge carrier separation while maintaining structural stability. The material’s superior performance was attributed to its increased specific surface area (4.75 m²/g vs 1.76 m²/g for Bi-MOF), reduced charge transfer resistance, and efficient generation of reactive oxygen species. Through radical scavenging experiments, it has been demonstrated that superoxide anion radicals (•O₂⁻) and holes (h⁺) are the primary active species. It is noteworthy that the Yb₃/Bi-MOF exhibits exceptional practicality, demonstrating stable performance across diverse water samples including rivers and lakes. After eight consecutive cycles, it maintained an 70 % removal efficiency. LC-MS analysis elucidated the pathway for the complete degradation of OTC into non-toxic intermediates. These findings not only offer a promising bifunctional material for antibiotic wastewater treatment but also provide valuable insights for the rational design of lanthanide-doped MOF photocatalysts, highlighting the immense potential of combining adsorption with photocatalysis for efficient environmental remediation.