1. [Spectroscopy Characterization of Anthracite Oxide].
- Author
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Huang DB, Chuan XY, and Cao X
- Abstract
With high degree of metamorphism and carbon content, anthracite is commonly used for activated carbon. The structural properties of anthracite play a decisive role in its materialization, while with chemical oxidation, anthracite structure can be purposefully improved. The anthracite oxide was prepared via acid leaching and oxidizing, using high carbon content and low ash content anthracite from Zhaotong, Yunnan Province, China. The structural and spectroscopy characteristics of anthracite and anthracite oxide were acquired with X-ray diffraction (XRD), Raman spectroscopy and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The results show that crystallites in anthracite have intermediate structures between graphite and amorphous. Compared with bitumite and lignite, its structure order degree lies between graphite and low metamorphic coals with relatively high average diameter of coal crystallites(La) and average height of coal crystallites (Lc). The process of anthracite oxidation can be modeled in two steps, the edge of crystal was curled and destroyed with strong oxidation, with the generation of CO group and intercalation of HNO3/H2SO4 into the edge layers, leading to the reducing of lateral sizes; HNO3/H2SO4 were continually intercalated into crystals, resulted in the increase of interlayer spacing (d(002)) from 0.351 to 0.361 nm, and the number of stacked layers dropped to 4.5 from 6 due to exfoliate. ID1/IG in Raman spectroscopy increased from 1.9 to 2.0, with full width at half maximum (FWHM) of G bond and intensity of D2 bond increasing from 63 to 68 and 10.26 to 13.78. Numbers of new —C—O—, CO, —NO2 groups generated, leading to the decrease of oxygen-containing functional groups content from 0.11 to 0.42. After HNO3/H2SO4 oxidation, the aromaticity (fa) of anthracite oxide increases, with the decrease of structure order degree and more-over a lot of active reaction sites generates in the process. The oxidation of anthracite enables anthracite has great potential in the application of porous carbon preparation.
- Published
- 2016