Superior and Effective Removal of Metformin From Aqueous Solution Using Zr-MOF-NH-(CH2)3-SO3H Novel Nano Adsorption

Abstract

Metformin, a widely used medication, is primarily employed as an anti-hyperglycemic drug for diabetes management, with emerging roles in cancer suppression and as a potential weight loss treatment. The widespread use of this medication has led to its accumulation in aquatic and sewage environments. Even in small quantities, this drug poses risks to both humans and other animals, particularly in aquatic environments. In this study, alkyl and sulfonic groups were linked to a metal–organic framework (MOF) for Zr-MOF-NH-(CH₂)₃-SO₃H synthesis using a post-synthetic method. Subsequently, the performance of Zr-MOF-NH-(CH₂)₃-SO₃H as a nano-adsorbent for the removal of metformin pharmaceutical pollutants was investigated. Under optimal conditions (pH = 9, contact time 90 min, adsorbent dose = 0.1 g/L, and metformin concentration 25 ppm), the maximum adsorption capacity for removal was approximately 160 mg/g. The interactions between the framework and metformin, the effect of pH on these interactions, and the possible mechanisms were investigated. The final results showed that the Zr-MOF-NH-(CH₂)₃-SO₃H framework has a high adsorption capacity to remove the metformin drug, and this high adsorption probably occurs mostly via electrostatic attraction, which results in more interactions, such as H-bonding, π-π, and acid and base interactions. Additionally, the freely rotating alkyl chains (−(CH₂)₃SO₃H) in the MOF can further enhance the material's ability to capture metformin by improving the penetration of metformin into the framework, thus significantly enhancing the adsorption performance. This study demonstrates the potential of Zr-MOF-NH-(CH₂)₃-SO₃H as an effective nano-adsorbent for mitigating pharmaceutical pollutants in aquatic environments.