Effectiveness of waste-derived MIL type MOFs in removing PFOA and PFAS pollutants for environmental remediation

Elimination of perfluorooctanoic acid (PFOA), a persistent pollutant that is toxic to human and ecosystem health, is important. In this study, three adsorbents, C-101, W-101, and NW-101, were evaluated. W-101 was modified by diamine ethyl modification to enhance the number of PFOA adsorption sites. The results showed that W-101 (42.7 mg g^-1) had better PFOA adsorption capacity than C-101 (12.3 mg g^-1), and NW-101 (698.4 mg g^-1) was the best. The Langmuir model correctly described the isotherms of PFOA adsorption, and the pseudo-second-order kinetic model fitted the process. NW-101 exhibited an excellent adsorption efficiency, as it reached the equilibrium within 7 min, and also revealed higher reusability due to the stable structure of the amine-grafted structure; therefore, NW-101 proved very efficient in PFOA removal. The new method used the bark of poplar trees to prepare MIL-101(Cr) adsorbents with surface areas of 3341, 2767, and 2374 m² g^-1 for C-101, W-101, and NW-101, respectively. This cost-effective, eco-friendly method utilizes renewable raw materials, minimizes environmental impact, and represents a significant advance in PFOA removal and thermal material research.