Construction of functionalized Zr-MOF and its performance in removing oxytetracycline from wastewater

This study addresses the pollution of oxytetracycline (OTC) in aquatic environments by synthesizing an amino-functionalized zirconium-based metal-organic framework (NH₂-UiO-66) via a solvothermal method using zirconium chloride and 2-aminoterephthalic acid, for the efficient removal of OTC from wastewater. Systematic investigations were conducted on the effects of temperature, solution pH, adsorbent dosage, adsorption time, and initial concentration of OTC on the adsorption performance. The results indicate that the adsorption capacity of NH₂-UiO-66 for OTC is approximately 2.8 times that of the non-functionalized UiO-66. The adsorption behavior followed the pseudo-second-order kinetics model and the Langmuir isotherm model, with a theoretical maximum adsorption capacity of 81.43 mg·g^-1. The adsorption process was identified as a spontaneous, monolayer chemisorption process(ΔG⁰ < 0, ΔH⁰ > 0, ΔS⁰ > 0). The material exhibited excellent stability and reusability, retaining 83.6% of its initial adsorption capacity after five adsorption-desorption cycles. Moreover, in tests with various real water samples, the removal efficiency of OTC by NH₂-UiO-66 remained above 90%, demonstrating its potential for application in complex water environments. This research provides a reference for the development of efficient and stable materials for antibiotic wastewater treatment.