College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
Bioresour Technol. 2019 Aug;286:121385. doi: 10.1016/j.biortech.2019.121385. Epub 2019 Apr 27.
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.
螺旋藻（SP）在中低温（180-280°C）水热碳化（HTC）中的氮转化（N-转化）机制。通过傅里叶变换红外光谱（FTIR）、X 射线光电子能谱（XPS）、气相色谱-质谱联用（GC-MS）等分析方法研究了生物炭、液体和生物油中的 N-转化。结果表明，温度可显著影响氮的演变。在 180-200°C 时，生物炭中蛋白氮（protein-N）和吡啶氮（pyridine-N）的含量分别下降了 23.01%和 9.51%。相比之下，无机氮（inorganic-N）和季氮（quaternary-N）的含量分别增加了 16.99%和 16%。在 HTC 过程中，蛋白-N 水解和 Maillard 反应产生了关键的中间化合物，包括胺、酰胺和 N-杂环化合物。在 200-280°C 时，无机氮明显从固体转化为液体。随着温度的升高，它会增强吡咯-N 和吡啶-N 的聚合，这会导致生物油中芳香族 N-杂环化合物（如腈和吲哚衍生物）的显著增加。本研究提出了一种 SP HTC 的 N-转化机制。
