Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments
| Autor: | Ravi Subramanyam, Stranick Michael A, Long Pan, Laurence Du-Thumm, Viktor Dubovoy |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Materials science
General Chemical Engineering Aluminum Hydroxide 010402 general chemistry 01 natural sciences General Biochemistry Genetics and Molecular Biology chemistry.chemical_compound Microscopy Electron Transmission X-Ray Diffraction X-ray photoelectron spectroscopy Aluminosilicate Spectroscopy Fourier Transform Infrared Fourier transform infrared spectroscopy Aqueous solution General Immunology and Microbiology 010405 organic chemistry General Neuroscience Mesoporous silica Silicon Dioxide 0104 chemical sciences Chemistry Mesoporous organosilica chemistry Chromatography Gel Nanoparticles Thermodynamics Hydroxide Aluminum Silicates Mesoporous material Porosity Nuclear chemistry |
| Zdroj: | Journal of Visualized Experiments. |
| ISSN: | 1940-087X |
| DOI: | 10.3791/55423-v |
| Popis: | An aqueous suspension of nanogibbsite was synthesized via the titration of aluminum aqua acid [Al(H(2)O)(6)](3+) with L-arginine to pH 4.6. Since the hydrolysis of aqueous aluminum salts is known to produce a wide array of products with a wide range of size distributions, a variety of state-of-the-art instruments (i.e., (27)Al/(1)H NMR, FTIR, ICP-OES, TEM-EDX, XPS, XRD, and BET) were used to characterize the synthesis products and identification of byproducts. The product, which was comprised of nanoparticles (10-30 nm), was isolated using gel permeation chromatography (GPC) column technique. Fourier transform infrared (FTIR) spectroscopy and powder X-ray diffraction (PXRD) identified the purified material as the gibbsite polymorph of aluminum hydroxide. The addition of inorganic salts (e.g., NaCl) induced electrostatic destabilization of the suspension, thereby agglomerating the nanoparticles to yield Al(OH)(3) precipitate with large particle sizes. By utilizing the novel synthetic method described here, Al(OH)(3) was partially loaded inside the highly ordered mesoporous framework of MCM-41, with average pore dimensions of 2.7 nm, producing an aluminosilicate material with both octahedral and tetrahedral Al (O(h)/T(d) = 1.4). The total Al content, measured using energy-dispersive X-ray spectrometry (EDX), was 11% w/w with a Si/Al molar ratio of 2.9. A comparison of bulk EDX with surface X-ray photoelectron spectroscopy (XPS) elemental analysis provided insight into the distribution of Al within the aluminosilicate material. Furthermore, a higher ratio of Si/Al was observed on the external surface (3.6) as compared to the bulk (2.9). Approximations of O/Al ratios suggest a higher concentration of Al(O)(3) and Al(O)(4) groups near the core and external surface, respectively. The newly developed synthesis of Al-MCM-41 yields a relatively high Al content while maintaining the integrity of the ordered silica framework and can be used for applications where hydrated or anhydrous Al(2)O(3) nanoparticles are advantageous. |
| Databáze: | OpenAIRE |
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