Enhanced hydrophobicity of modified ZIF-71 metal-organic framework for biofuel purification

• Published in: Polyhedron 2022-05, Vol.217, p.115736, Article 115736
• Main Authors: Tiempos-Flores, Norma, Hernández-Fernández, Eugenio, Rico-Barragan, Alan, Raziel Álvarez, J., Juárez-Ramírez, Isaías, Garza-Navarro, M.A., Rodríguez-Hernández, Joelis, Fonseca-García, Abril, Michaelis, David J., Davila-Guzman, Nancy E.
• Format: Article
• Language: English
• Subjects: Biofuels; Hydrophobicity; MOF; Purification; ZIF-71
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2022.115736

Porous materials along with high hydrophobicity become promising adsorbents for biofuel purification. Angle contact experiments revealed that the substitution of chlorine atom instead of bromine on ZIF-71 achieved the enhancement of the hydrophobicity in this new ZIF-71(ClBr)-SE. [Display omitted] Hydrophobic materials are desirable for biofuel purification applications. In this work, the atomic substitution of Cl atom with Br atom in the imidazole organic linker was carried out to produce a more hydrophobic ZIF-71, named ZIF-71(ClBr) and ZIF-71(ClBr)-SE for the material with an additional solvent exchange procedure. The physicochemical characterization revealed that ZIF-71(ClBr) and ZIF-71(ClBr)-SE are isostructural to ZIF-71, have a high surface area (769 and 969 m2/g), and are hydrophobic (126 and 130° water contact angle). As a proof of concept, D4 siloxane adsorption capacity onto ZIF-71(ClBr) and ZIF-71(ClBr)-SE was estimated (1.76 and 2.66 mg/g, respectively). Furthermore, a superior adsorption capacity was obtained when ZIF-71(ClBr)-SE was used due to its higher hydrophobic nature, and similar results were obtained with ZIF-8, used as a frame of reference. Therefore, the high surface area and the hydrophobic nature of ZIF-71(ClBr)-SE make it compelling material for biofuel purification applications.