1. Speciation and transformation of nitrogen for spirulina hydrothermal carbonization.
- Author
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Xiao H, Zhai Y, Xie J, Wang T, Wang B, Li S, and Li C
- Subjects
- Hydrolysis, Organic Chemicals, Temperature, Nitrogen, Spirulina
- Abstract
Nitrogen conversion (N-conversion) mechanism of spirulina (SP) in hydrothermal carbonization (HTC) was investigated under medium-low temperature (180-280 °C). N-conversion in bio-char, liquid and bio-oil were studied by FTIR, XPS, GC-MS and other analytical methods. Results indicated that the temperature could significantly affect the evolution of nitrogen. At 180-200 °C, the content of protein-N and pyridine-N in bio-char fell 23.01% and 9.51% respectively. In contrast, the contents of inorganic-N and quaternary-N increased by 16.99% and 16% respectively. Protein-N hydrolysis and Maillard reaction produced the key intermediate compounds, including amines, amides and N-heterocyclic compounds during the HTC. At 200-280 °C, the inorganic-N was obviously converted from solid to liquid. With the increased of temperature, it would enhance the polymerization of pyrrole-N and pyridine-N, which could cause the significant increase of aromatic N-heterocyclic compounds (e.g., nitriles and indole derivatives) in bio-oil. A N-conversion mechanism of SP HTC was proposed in this study., (Copyright © 2019 Elsevier Ltd. All rights reserved.)
- Published
- 2019
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