Use of FTIR combined with forms of water to study the changes in hydrogen bonds during low-temperature heating of lignite

Xiangchun Liu, Tsuyoshi Hirajima, Moriyasu Nonaka, Anggoro Tri Mursito, Keiko Sasaki

研究成果: Contribution to journalArticle査読

14 被引用数 (Scopus)

抄録

The changes in the hydrogen bonds (HBs) of three types of Indonesian lignite during low-temperature heating were investigated. The amount of water loss was determined by weighing the samples before and after heating in an oven. The changes in the number of the different types of HBs were determined using Fourier transform infrared spectroscopy coupled with types of water in lignite. The number of peak positions and absorption bands in each spectrum was determined by curve-fitting analysis with a Gaussian function. The quantified integrated area of aromatic hydrogen atoms was used to accurately investigate the changes in the HBs. The results show that at low temperatures (T ≤ 50°C), free water is mainly removed, and the HBs broken are those between free water molecules. However, at medium temperatures (50 <T ≤ 100°C), bound water is mainly removed. The number of HBs significantly changes because of the breaking of bound water molecule HBs and bound water cluster–carboxyl group HBs, and the formation of nonfreezable moisture HBs. At high temperatures (100 <T < 125°C), nonfreezable moisture can be released. The number of HBs changes as a result of competition between the removal of nonfreezable moisture and the increase in the number of carboxyl groups. At higher temperatures (T ≥ 125°C), the moisture remaining in lignite is thermal decomposition moisture. In addition, the rate of decomposition of carboxyl groups is higher than the rate of generation, which means that the number of HBs markedly decreases at higher temperatures.

本文言語英語
ページ(範囲)185-193
ページ数9
ジャーナルDrying Technology
34
2
DOI
出版ステータス出版済み - 1 25 2016

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Physical and Theoretical Chemistry

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