| 1. |
- Dyer, Chris, et al.
(författare)
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Surface hydration of aqueous γ-Al2O3 studied by Fourier transform Raman and infrared spectroscopy—I. Initial results
- 1993
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Ingår i: Spectrochimica Acta. Part A, Molecular Spectroscopy. - 0584-8539. ; 49:5-6, s. 691-705
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Tidskriftsartikel (refereegranskat)abstract
- The hydration of γ-Al2O3 has been studied by Fourier transform (FT) Raman and infrared (IR) spectroscopy, and by X-ray diffraction (XRD). The initial findings are presented, along with a discussion of the possible causes for the major spectral changes that occur after hydration. The aims of the study and ongoing research are described.
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| 2. |
- Klug, Otto, et al.
(författare)
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A novel method for investigation of dibasic aromatic acids on oxidized aluminium surfaces by NIR-FT-SERS
- 1997
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Ingår i: Progress in Fourier Transform Spectroscopy. - Vienna : Springer Vienna. ; , s. 649-651
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Konferensbidrag (refereegranskat)abstract
- A new technique is presented for detecting dibasic aromatic acids on an SERS-inactive oxidized aluminium foil by utilizing near-infrared Fourier-transform surface-enhanced Raman spectroscopy (NIR-FT-SERS). Identification of adsorbed ortho-, meta- and para-phthalic acids on a typical anodic foil of electrolytic capacitors From electrolytes containing 1 ppm substrate was successfully accomplished.
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| 3. |
- Liu, Wenxin, et al.
(författare)
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A flexible method of carbonate determination using an automatic gas analyzer equipped with an FTIR photoacoustic measurement chamber
- 1999
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Ingår i: The Analyst. - 0003-2654 .- 1364-5528. ; 124:3, s. 361-365
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Tidskriftsartikel (refereegranskat)abstract
- A Fourier transform infrared spectrometer was employed to determine automatically the total inorganic carbonate (TIC) in solids and waters, based on active photoacoustic absorption of infrared light by carbon dioxide. A 2.0 l reactor, connected to the spectrometer, is immersed in water-bath at 20 °C. After purging with pure N2, 5 ml of 0.5 mol l–1 HClO4 are injected into 50 ml of solid suspension or solution with continuous stirring. The specific absorption of infrared light by the CO2 evolved induces corresponding fluctuations of temperature and pressure in a measurement chamber. Accordingly, photoacoustic signals, with frequencies dependent on the absorbed wavelengths, are generated and measured by the chamber microphones in the form of an absorption spectrum and concentration. For solids, the method exhibits a linear response up to 120 mg of CaCO3 with a detection limit of 0.02 mg; in the case of waters, these figures of merit are 36.4 mmol l–1 and 3 µmol l–1 NaHCO3, respectively. Since proton consumption by TIC in clay minerals may commonly influence the evaluation of surface acid–base properties, the methodology was applied to determine TIC in three natural illite samples of different origins. In addition, some potential interferences and modifications of this method are discussed.
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| 4. |
- Mohammed-Ziegler, Ildiko, et al.
(författare)
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Adsorption of pinosylvin onto different species of fresh and stored wood
- 2010
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Ingår i: Materials Science: An Indian Journal. - 0974-7486. ; 6:4
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption of pinosylvin- a natural antifungal agent - on wood was studied byRamanmicroprobe technique. The adsorption properties of twelve different European wood species were compared. The effect of solvents used, heat treatment, and prolonged storage of the samples on pinosylvin adsorption ability was analysed by means of the Raman intensity ratios of characteristic lines. Itwas found that the surface concentration of pinosylvin increased when the Lewis acidity of the solvent increased. Besides, adsorption of pinosylvin was less efficient on during prolonged storage the surface of wood became more hydrophobic after prolonged sample storage. In case of heat treatment (120ï‚°C, 3 h) no remarkable effect on the amount of adsorbed pinosylvin was observed. Simultaneously, the intensity of the fluorescence background increases. Moreover, the possible influence of B.E.T. specific surface area and lignin content (described by the kappavalue) on the amount of adsorbed pinosylvin was investigated.As revealed, B.E.T. specific surface area did not vary significantly between the different wood species, and therefore it has no significant effect on the efficiency of pinosylvin adsorption. However, the surface concentration of pinosylvin seems to increas with the lignin content. The amount of solvent residue in each sample wasmeasured by diffuse reflectance infrared Fourier transform (DRIFT) technique. For a few wood samples (e.g. pine heartwood, ash, and Hungarian oak) UV-Raman scattering was used to characterize the aromatic components of these wood species. The morphology of the samples was investigated with the aid of scanning electron microscopy (SEM) images. Furthermore, the B.E.T. specific surface area was found not to vary significantly between the different wood species, and therefore it has no significant effect on the efficiency of pinosylvin adsorption. However, the surface concentration of pinosylvin seems to increas with the lignin content. DRIFT spectroscopy was found to be useful to detect solvent residue in the wood samples and the evaporation of polar solvents is a rather slow process. However, it was not possible to detect adsorbed pinosylvin by DRIFT measurements, due to the low concentration and the lack of characteristic frequencies differing from other wood constituents.
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| 5. |
- Mohammed-Ziegler, Ildikó, et al.
(författare)
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Mechanism of the adsorption process of pinosylvin and some polyhydroxybenzenes onto the structure of lignin
- 2004
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Ingår i: Vibrational Spectroscopy. - : Elsevier BV. - 0924-2031 .- 1873-3697. ; 36:1, s. 65-72
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Tidskriftsartikel (refereegranskat)abstract
- The lignin Induline AT was used as model substrate to observe the adsorption of pinosylvin, trans-stilbene, pyrocatechol, resorcinol, hydroquinone, pyrogallol and phloroglucinol. Prior to adsorption the adsorbates were dissolved in diethylether. Infrared spectra of adsorbed compounds were recorded using the diffuse reflectance infrared Fourier transform (DRIFTS) technique. Far IR spectra of the adsorbed pinosylvin and polyhydroxybenzenes were used to facilitate the interpretation on the mechanism of adsorption. Vibrational analysis by quantum chemical calculations, available for most of the polyhydroxybenzenes, were utilized. The interaction between adsorbed species and lignin was found to be mainly mediated through the formation of hydrogen bonds.
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