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Adsorption performance of UiO-66 towards organic dyes: effect of activation conditions

Vaghar Mousavi, D ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1016/j.molliq.2020.114487
  3. Publisher: Elsevier B.V , 2020
  4. Abstract:
  5. The Zr-based metal-organic framework (MOF, UiO-66) was synthesized solvothermally. The synthesized UiO-66 was activated using different solvents (acetone, chloroform, and ethanol) via two activation methods of centrifugation and Soxhlet extraction over different periods (1–10 days). The crystalline structure and morphology of the synthesized UiO-66s were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, and field-emission scanning electron microscopy (FESEM) techniques. The adsorption behaviors of the synthesized UiO-66s were then investigated by selecting anionic methyl red (MR) and cationic methylene blue (MB) as the model dyes. It was found that a change in activation solvent and activation method would alter the physical properties of UiO-66, such as surface area, pore-volume, pore diameter, and surface charge. Experimental adsorption tests demonstrated that UiO-66 activated by ethanol via the Soxhlet extraction method for five days (abbreviated as ES-5) presented higher MR uptake capacity (243 mg/g) than the other synthesized UiO-66s, ascribed to its large surface area and total pore volume. Furthermore, it was found that the uptake capacity of ES-5 for cationic MB and anionic MR dyes increased and decreased, respectively, with raising the solution pH. This resulted in superior adsorption selectivity of MB over MR at pH 9.1. All in all, the findings of this work showed that the Soxhlet extraction method holds great promise for the activation of different MOFs. © 2020 Elsevier B.V
  6. Keywords:
  7. Activation solvent ; Dye removal ; Metal-organic framework ; Selective adsorption ; UiO-66 ; Acetone ; Chemical activation ; Chlorine compounds ; Dyes ; Ethanol ; Extraction ; Field emission microscopes ; Metal-organic frameworks ; Morphology ; Organic polymers ; Organic solvents ; Organometallics ; Scanning electron microscopy ; Activation conditions ; Adsorption behavior ; Adsorption performance ; Adsorption selectivity ; Crystalline structure ; Field emission scanning electron microscopy ; Large surface area ; Nitrogen adsorption desorption ; Gas adsorption
  8. Source: Journal of Molecular Liquids ; 2020
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0167732220345281