Magnetic aluminum-based metal-organic frameworks (Fe3O4@Al-MOFs) are being explored as advanced adsorbent materials for the removal of perfluorooctanoic acid (PFOA), a widely detected per- and polyfluoroalkyl substance (PFAS) in contaminated water. In this study, microparticle forms of Magnetic metal-organic frameworks (MMOFs) were synthesized using green chemistry principles to minimize environmental impact. The synthesis was carried out via solvothermal and solvent-free methods, using three different ligands: terephthalic acid (H2BDC), amino-terephthalic acid (NH2BDC), and tetrafluoroterephthalic acid (F4BDC), in combination with solvents such as ethanol, water, and DMF. The structural and chemical properties of the materials were confirmed using PXRD for crystallinity, SEM-EDS and TEM for morphology and elemental distribution, FTIR-ATR for functional groups, and BET for surface area. The results confirmed the successful formation of the hybrid materials and their magnetic functionalization. Adsorption performance was evaluated through fixed-time and kinetic tests, as well as multi-cycle adsorption–desorption experiments. Post-cycle PXRD and SEM analysis were used to assess structural stability. The results demonstrated that the ethanol-based solvothermal synthesis, particularly with H2BDC, yielded the most promising adsorbent, achieving a PFOA removal efficiency of 99.8% within a single adsorption cycle from a initial PFOA concentration of 108 μg/L. Despite its relatively low crystallinity, the porosity, accessible surface area, and defects play a critical role in adsorption efficiency. Furthermore, this material exhibited promising reusability over ten adsorption cycles, although a progressive decrease in performance was observed. A regeneration efficiency of 82.9% was achieved, highlighting its promising reusability and the potential for efficient recovery of adsorption performance. The fluorinated sample synthesized via a solvent-free approach also demonstrated excellent adsorption efficiency (95.7%) and was the most environmentally sustainable among the tested methods. In contrast, the amino-functionalized MMOF in ethanol showed lower adsorption performance (76.9%). These findings underscore the importance of selecting the appropriate solvent, ligand, and synthesis route in designing MMOFs for PFAS remediation. In particular, ethanol-based syntheses offer a practical and scalable pathway for effective water treatment applications.
I framework metallo-organici magnetici a base di alluminio (Fe3O4@Al-MOFs) sono oggetto di studio come materiali adsorbenti avanzati per la rimozione dell’acido perfluoroottanoico (PFOA), una sostanza per- e polifluoroalchilica (PFAS) ampiamente rilevata nelle acque contaminate. In questo studio, forme microparticellari di MMOF sono state sintetizzate seguendo i principi della chimica verde, al fine di ridurre al minimo l’impatto ambientale. La sintesi è stata condotta tramite metodi solvotermici e solvent-free, utilizzando tre differenti ligandi: acido tereftalico (H2BDC), acido ammino-tereftalico (NH2BDC) e acido tetrafluoro-tereftalico (F4BDC), in combinazione con solventi quali etanolo, acqua e DMF. Le proprietà strutturali e chimiche dei materiali sono state confermate tramite PXRD per la cristallinità, SEM EDS e TEM per la morfologia e la distribuzione elementare, FTIR per i gruppi funzionali e BET per l’area superficiale. I risultati hanno confermato con successo la formazione dei materiali ibridi e la loro funzionalizzazione magnetica. Le prestazioni di adsorbimento sono state valutate mediante test a tempo fisso e cinetici, nonché attraverso esperimenti di adsorbimento–desorbimento su più cicli. Le analisi PXRD e SEM post-ciclo sono state utilizzate per valutare la stabilità strutturale. I risultati hanno dimostrato che la sintesi solvotermica in etanolo, in particolare con H2BDC, ha prodotto l’adsorbente più promettente, raggiungendo un’efficienza di rimozione del PFOA pari al 99.8% in un singolo ciclo di adsorbimento da una concentrazione iniziale di PFOA di 108 μg/L. Nonostante la relativa bassa cristallinità, la porosità, l’area superficiale accessibile e i difetti giocano un ruolo critico nell’efficienza di adsorbimento. Inoltre, questo materiale ha mostrato una promettente riusabilità per dieci cicli di adsorbimento, sebbene sia stata osservata una progressiva diminuzione delle prestazioni. È stata raggiunta un’efficienza di rigenerazione dell’82.9%, evidenziando la sua buona riusabilità e il potenziale per un recupero efficiente delle prestazioni di adsorbimento. Anche il campione fluorurato sintetizzato tramite un approccio privo di solventi ha dimostrato un’eccellente efficienza di adsorbimento (95.7%) ed è risultato essere il più sostenibile dal punto di vista ambientale tra i metodi testati. Al contrario, l’MMOF funzionalizzato con gruppi amminici in etanolo ha mostrato prestazioni di adsorbimento inferiori (76.9%). Questi risultati evidenziano l’importanza della scelta di solvente, legante e metodo di sintesi nella progettazione di MMOF per la rimozione dei PFAS. In particolare, le sintesi in etanolo offrono un approccio pratico e scalabile per applicazioni efficaci nel trattamento delle acque.
Synthesis of magnetic al-based metal-organic framework (Fe3O4@Al-MOF) for capture of PFAS in the treatment of wastewater
Paucar Suntaxi, Kelly Nicole
2024/2025
Abstract
Magnetic aluminum-based metal-organic frameworks (Fe3O4@Al-MOFs) are being explored as advanced adsorbent materials for the removal of perfluorooctanoic acid (PFOA), a widely detected per- and polyfluoroalkyl substance (PFAS) in contaminated water. In this study, microparticle forms of Magnetic metal-organic frameworks (MMOFs) were synthesized using green chemistry principles to minimize environmental impact. The synthesis was carried out via solvothermal and solvent-free methods, using three different ligands: terephthalic acid (H2BDC), amino-terephthalic acid (NH2BDC), and tetrafluoroterephthalic acid (F4BDC), in combination with solvents such as ethanol, water, and DMF. The structural and chemical properties of the materials were confirmed using PXRD for crystallinity, SEM-EDS and TEM for morphology and elemental distribution, FTIR-ATR for functional groups, and BET for surface area. The results confirmed the successful formation of the hybrid materials and their magnetic functionalization. Adsorption performance was evaluated through fixed-time and kinetic tests, as well as multi-cycle adsorption–desorption experiments. Post-cycle PXRD and SEM analysis were used to assess structural stability. The results demonstrated that the ethanol-based solvothermal synthesis, particularly with H2BDC, yielded the most promising adsorbent, achieving a PFOA removal efficiency of 99.8% within a single adsorption cycle from a initial PFOA concentration of 108 μg/L. Despite its relatively low crystallinity, the porosity, accessible surface area, and defects play a critical role in adsorption efficiency. Furthermore, this material exhibited promising reusability over ten adsorption cycles, although a progressive decrease in performance was observed. A regeneration efficiency of 82.9% was achieved, highlighting its promising reusability and the potential for efficient recovery of adsorption performance. The fluorinated sample synthesized via a solvent-free approach also demonstrated excellent adsorption efficiency (95.7%) and was the most environmentally sustainable among the tested methods. In contrast, the amino-functionalized MMOF in ethanol showed lower adsorption performance (76.9%). These findings underscore the importance of selecting the appropriate solvent, ligand, and synthesis route in designing MMOFs for PFAS remediation. In particular, ethanol-based syntheses offer a practical and scalable pathway for effective water treatment applications.File | Dimensione | Formato | |
---|---|---|---|
2025_07_Paucar_Thesis.pdf
accessibile in internet solo dagli utenti autorizzati
Descrizione: Thesis Text
Dimensione
43.85 MB
Formato
Adobe PDF
|
43.85 MB | Adobe PDF | Visualizza/Apri |
2025_07_Paucar_Executive Summary.pdf
accessibile in internet solo dagli utenti autorizzati
Descrizione: Executive Summary text
Dimensione
4.86 MB
Formato
Adobe PDF
|
4.86 MB | Adobe PDF | Visualizza/Apri |
I documenti in POLITesi sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/10589/240615