Insight into the molecular mechanism of organic pollutants’ adsorption on magnetic ZIF-8 synthesized via a transformational route

Liu, Zhang ; Marquina, C. ; Han, Wei ; Kwan, Joseph K.C. ; Ibarra, M. Ricardo (Universidad de Zaragoza) ; Yeung, King Lun

Resumen: This study presents the synthesis of Fe3O4@Zeolite Imidazolate Framework-8 (Fe3O4@ZIF-8), a novel magnetic core–shell adsorbent engineered for enhance adsorption of organic pollutants. The process begins with the formation of spherical magnetite aggregates (i.e., Fe3O4) via a solvothermal method, using polyacrylic acid for stabilization and capping. A ZIF-8 shell is then grown through a sol gel process followed by reaction with 2-methylimidazole, resulting in a crystalline shell approximately 60 nm thick. Characterization techniques, including energy dispersive X-ray analysis and X-ray diffraction, confirm the successful preparation of Fe3O4@ZIF-8. The adsorption capabilities were evaluated using methylene blue (MB) and diclofenac sodium (DCF) as model pollutants. Fe3O4@ZIF-8 demonstrated rapid removal efficiencies, with 98 % removal of MB (6.01 × 10-4 mg·g−1·min−1) and DCF (4.43 × 10-4 g·mg−1.min−1) within 15 and 30 min, respectively, significantly outperforming conventional activated carbon. Thermodynamic studies indicate that the adsorption processes are spontaneous; enthalpic changes drive MB adsorption, while DCF is influenced by entropic factors. Molecular modeling reveals preferential adsorption behaviors on different ZIF-8 facets, with stronger interactions for MB due to π-π stacking and hydrogen bonding. These findings underscore the potential of Fe3O4@ZIF-8 as an effective adsorbent for water purification, highlighting its substantial adsorption capacity (73.2 mg·g−1 for MB and 53.8 mg·g−1 for DCF), stability, and reusability.

Idioma: Inglés

DOI: 10.1016/j.seppur.2024.130006

Año: 2024

Publicado en: Separation and Purification Technology 356, Part B (2024), 130006 [10 pp.]
ISSN: 1383-5866

Financiación: info:eu-repo/grantAgreement/EC/H2020/760928/EU/BIOmaterial RIsk MAnagement/BIORIMA
Financiación: info:eu-repo/grantAgreement/ES/MCIU/RTC-2017-6620-1
Financiación: info:eu-repo/grantAgreement/ES/MICIU/PID2019-106947RB-C21

Tipo y forma: Article (PostPrint)

Área (Departamento): Área Física Materia Condensada (Dpto. Física Materia Condensa.)