Sulfur Pigments Synthesized from Zeolite LTA under Vacuum and in Air. XRD and Spectroscopic (UV−vis, FTIR, Raman, ESR, ESE) Characterization

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• 作者：Stanisł ; aw K. Hoffmann ; Janina Goslar ; Stefan Lijewski ; Iwona Olejniczak ; Aldona Jankowska ; Anna Werbiska ; Stanisł ; aw Kowalak
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2010
• 出版时间：September 1, 2010
• 年：2010
• 卷：49
• 期：17
• 页码：8192-8199
• 全文大小：383K
• 年卷期：v.49,no.17(September 1, 2010)
• ISSN：1520-5045

文摘

X-ray, UV−vis, FT-infrared, Raman, continuous wave, and pulsed ESR spectroscopy were applied to characterize pigments prepared at 500 °C under vacuum or in air from mixtures of zeolite A (LTA) with sulfur (40 wt %) and anhydrous sodium sulfide (Na₂/S = 0.1−0.4). The samples maintained the LTA structure. Sample color results from an S₃⁻ absorption band and the shoulder of a UV band. The fingerprint and asymmetric stretch region of the IR spectra show that the pigments synthesized in air have more disordered structures. The S₂⁻/S₃⁻ratio was estimated from Raman spectra. The ESR spectra of S₃⁻ radicals show the existence of several phases visible as five different ESR components. Two components dominate: ideal [Na₄S₃⁻]³⁺ clusters and clusters existing in a disordered environment. The samples synthesized in air show a substantial distortion of local structure. Synthesis in vacuum leads to products containing about 20% of the ordered crystalline phase.