Enhanced visible-light photocatalytic degradation of antibiotics using aminoguanidine-functionalized iron-based...

The degradation of antibiotics in wastewater has gained significant attention due to the detection of high concentrations of these contaminants in water systems. Moreover, the complex composition of water matrices, which contain various coexisting components, poses significant challenges to their effective removal. To address this, in the present study, we investigated the selective photocatalytic degradation of antibiotics using metal-organic frameworks (MOFs). Thirteen types of MOFs were synthesized, among which aminoguanidine-functionalized iron-based MOFs (Fe-MOF-NH₂) exhibited the highest photocatalytic performance, achieving a 97 % degradation rate within 100 min under visible light irradiation. The enhanced photocatalytic activity of Fe-MOF-NH₂ can be attributed to the synergistic effect between the Fe sites and the amino groups, which facilitated the generation of reactive species. Theoretical calculations showed that the amino groups increased the electron density at the Fe centers by electron donation, which altered the redox behavior of Fe. Additionally, the amino groups formed hydrogen bonds with electrophilic groups in the antibiotic molecules and accelerated the degradation reaction by promoting the adsorption of pollutants and enhancing their activation on the MOF surface. Fe-MOF-NH₂ demonstrated excellent stability, maintaining its high degradation efficiency after five consecutive cycles. Mechanistic studies revealed that hydroxyl radicals (·OH) and holes (h⁺) were the primary reactive species driving the photodegradation process. These findings indicate that Fe-MOF-NH₂ is a promising photocatalyst for the efficient removal of antibiotics from wastewater, providing valuable insights into the design of MOF-based photocatalysts with enhanced activity for environmental remediation.